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FAQs on Corydoras Cat Disease 2

FAQs on: Corydoras Catfish Health 1, Cory Disease 3, Cory Disease 4,
FAQs on Corydoras Catfish Disease by Category
: Environmental, Nutritional (e.g. HLLE), Social, Infectious (Virus, Bacterial, Fungal), Parasitic (Ich, Velvet...), Genetic, Treatments,
Related Articles: Callichthyid Catfishes, Summer loving: cats in the garden, kittens in the kitchen by Neale Monks,

FAQs on: Corydoras Catfish 1,
& Corydoras Catfish Identification, Corydoras Catfish Behavior, Corydoras Catfish Compatibility, Corydoras Catfish Stocking/Selection, Corydoras Catfish Systems, Corydoras Catfish Feeding, Corydoras Catfish Reproduction,
FAQs on: Panda Corydoras, Pygmy Corydoras spp.,

FAQs on:
Callichthyids 1, Callichthyids 2,
FAQs on: Callichthyid Identification, Callichthyid Behavior, Callichthyid Compatibility, Callichthyid Selection, Callichthyid Systems, Callichthyid Feeding, Callichthyid Disease, Callichthyid Reproduction, Catfish: Identification, Behavior, Compatibility, Selection, Systems, Feeding, Disease, Reproduction,

Bronze Cory Help!!! 10/17/09
First off I want to say that your site has been a great deal of help. As a first time fish owner I have used your site as a resource in having a happy and thriving tank.
<Thanks for the kind words.>
I have had my 35 gallon fresh water tank since end of April. I followed the beginner guidelines in circulating the tank before I put in any fish. Right now I have four Rosey barbs, a rainbow shark, Pleco, and three bronze Corys and so far haven't had any problems until today.
<Sounds an interesting mix. While the Rosy Barbs and the Corydoras both appreciate somewhat cool water, Rosy Barbs can be "fin nippers" and work best in large groups (six or more specimens, a mix of males and females) so they busy themselves chasing one another around rather than other fish.
Rainbow Sharks can be feisty, and the Plec will get far too large for this aquarium. So you will have some problems to fix before too long.>
Icky, one of my Corys went missing this week. I searched the tank and he was no where to be found. Today, we did a 60% water change and put in some Columbian drift wood. After picking up a rock that was, until today, thought to be a safe tank decoration - out zooms icky the Cory catfish looking pretty rough. For the first couple of minutes of being free from his confines he was laying on his side. After a little more time passed he's sitting in his natural stationary, but upright, position. It looks as though the barbs made a meal of a few of his fins, and he has several spots that have been worn from trying to wiggle out from beneath the rock.
<Yes: Rosy Barbs will indeed nip at fish. For whatever reason, Corydoras are "sitting ducks" where nippy fish are concerned. I find that whereas Plecs and Synodontis keep out of the way, every time I've kept Corydoras with, say, Puffers or Ameca splendens, they've had their dorsal fins nipped.>
It looks as though he's on the track of pulling through, but you never know with fish. Do you have any advice on how to treat this situation?
<Beyond clean water, I'd not do anything else apart from separate them.
Corydoras fins heal very quickly, and like many catfish, they're likely to react badly to copper or formalin, so I wouldn't use either unless I absolutely had to. So move the school of Corydoras to an aquarium of their own, something 20 gallons upwards, and let them settle down and be happy.
Rosy Barbs sound like a poor choice of tankmate here. You might even get rid of the Rosy Barbs; when all is said and done, they're big fish (up to 15 cm/6 inches) not suited to 35 gallon tanks.>
I'm worried that icky may not make it.
<Cheers, Neale.>
Re: Bronze Cory Help!!! 10/17/09

The Rosey barbs and the Corys get along, they really mind to themselves or get chased every once in a while by the shark. Luckily the only issue we have had with the barbs is that they chase and nip at each other.
<What they do. If kept in large groups, six or more, and ideally more females (yellow-green) than males (pink) then they tend to settle down. In the right tank, a spacious subtropical system, they're superb fish.>
We are fairly certain that the reason why icky the Cory cat has had a good amount of his fins nipped off is because he was literally stuck under the rock but the barbs could still get to him.
<Whether he got stuck under the rock, or was hiding to avoid being nipped, is difficult to answer. Both explanations are possibilities.>
Right now the rough looking Cory looks as if he is acting normal, but he really looks rather rough.
<Indeed. Usually, Corydoras heal very well. The common species like Bronze and Peppered Corydoras have become so popular precisely because they are so durable.>
We know of the issue with the Pleco out growing our tank. We have a home for him when he gets big enough in a 300 gallon brackish cichlid tank at a restaurant that we frequent.
<A home perhaps, but a bad one. Plecs ARE NOT brackish water fish.>
There is also a home for him at the Koi fish pond at the local botanical gardens.
<Unless this Koi pond is somewhere tropical, then that's not an option either. These fish die when exposed to water temperatures below 20 C (68 F) for any length of time. In the US for example, Southern Florida is the only place where these fish are likely to survive outdoors in an unheated pond.>
We've made sure that he will have a place to go when we can no longer care for him.
<Hmm... not impressed so far with the options.>
Looks as if we'll just have to wait and see how icky fairs. Keep your fingers crossed for us! Thanks for the tips!
<Happy to help.>
Also, about the barbs - we'll definitely consider trading them in for more suitable tank mates. Any recommendations??
<Depends, and the thing with many schooling fish is that if you don't keep enough, many species can become nasty, even Danios. One of the single best schooling fish species in the trade is the X-Ray Tetra (Pristella maxillaris). This species is very hardy and very peaceful; it is also rather pretty. I don't care much for the albino form, but it exists if that sort of thing amuses.>
Much appreciation, Kristin
<Cheers, Neale.>

Corydoras with a Possible Problem? Env. -- 08/23/09
Hello Crew -
You have been very helpful to me in the past, and I am hoping that you can help me again. This time, my issue is with some Corydoras catfish. I have three of them in my community tank, along with three platys and three mollies in a 23 gal tank. Two days ago, I woke up to one of my platys laying on the bottom of the tank dead, though she was behaving normally and eating just fine the day before. This upset me a lot, but I scooped her out and proceeded to put the rest of the fish into a bucket temporarily so that I could scrub out their tank since I did not know what had killed her.
<Mmmm... you may have "killed" your biological filter thus>
I scrubbed the tank walls down, vacuumed out the gravel thoroughly, and rinsed and wiped the ornaments thoroughly, paying special attention to the ornament that I found her lying half-against. I even changed the carbon in the filter, just to be safe. I put in my dechlorinator and stress coat (because I ended up changing about half of the water and cleaning the ornaments, and figured the slime coat might be altered some) according to the directions listed on the backs of the bottles. Honestly, I do not know if any of this has to do with the issue I am having, but I wanted to give you as much information as possible.
Yesterday, one of the Corydoras catfish started acting oddly. Usually, all of my Corys stay basically at the bottom, swimming around and foraging, and occasionally come to the top for air and swim right back down, as they should do. But yesterday, this Cory started swimming around close to the top of the tank. Not consistently - he still goes back down to the bottom and stays there most of the time, but I have never known any of my Corys to go to the top for any longer than their little breath-trips before.
Worried that he might have something wrong with him, since the behavior was irregular for him, I took him out, and put him by himself in a goldfish bowl (1.5 gals). I know that is not the best place for him, but I have no other tank to put him in where I can isolate him,
<I would return this fish to the main system. Not likely to live in the bowl, and very unlikely has anything "catching">
and I have been keeping the bowl very clean, and the temperature and pH steady at 78 degrees and 7.4 pH, and I have kept the water level low in there so that there is lots of water surface for him to get air from. I have been feeding him one Hikari Sinking Wafer at morning and night, and he does not seem to be touching them, though he swims around like normal now and does not head for the top as he did in the community tank. And now, back in the community tank, the other two Corys are acting the same way as
he was.
<Yes; environmental>
I have not moved them because I do not think there is room for the other two in the bowl with him. None show signs of any disease I am aware of (Ich, parasites, etc) - no white spots, no clamped fins, and the two in the community tank are eating fine. Is there something wrong with my Corys,
or am I freaking out a little too much?
<The water... system... is almost assuredly "at fault" here.>
And if there is something wrong - what, and what do I do?
<Look into boosting biological filtration. Read here:
and the linked files above till you understand>
Thank you for any answer -
<Welcome. Bob Fenner>

Sick Corydoras 8/18/09
Hello everyone. I was hoping you could answer a question for me.
<Fire away!>
Today, I noticed one of my Cory cats acting kind of strange. It was kind of flipping out, scratching each gill simultaneously on the substrate while swimming. Seems healthy, swimming normal now. Does not have any marks on him, spots etc. Have you ever seen them do this before?
<Does happen, yes.>
I tried doing a search on your site and did not see anything.
<Do review possibly sources of toxicity: paint fumes, insect sprays, etc.
Corydoras, being air-breathers, are peculiarly sensitive to these things.
Naturally, also review the usual things. You should have 0 ammonia, 0 nitrite, and a steady pH. Catfish are stuck at the bottom of the tank, so poor water circulation is another problem. Corydoras want shallow water (no more than 30 cm deep), low to moderate tropical conditions (22-24 degrees C for most species), and brisk water circulation (around 4-6 times the volume of the tank in turnover per hour).>
I do want to point out that back in June I had a bout with Whitespot
(probably velvet or Ich), which is gone now (had a temp drop and noticed this the next day). Treated with high temp (87 degrees 11 days) , extra salt (11 days), Maracide (10 days) and Melafix (7 days).
<Some medications stress catfish more severely than other fish, and using more than one medication makes things doubly risky. For Ick, the salt/heat protocol is the way to treat catfish.>
I hope this is not making a come back. All fish look fine, except for one neon with a little fin damage.
<Do review water quality; fin damage, i.e., Fin Rot, is a classic symptom of opportunistic bacterial infections.>
Tank - 40 gal, measurements amm - 0 nitrite 0, nitrate 15 to 20, PH 7.4.
I have done 2 - 25 % water changes per week since beginning of June. 2 Aquaclear 50s on tank, so I don't think it is water quality.
Fish - Neon Tetra - 12
Colombian Tetra - 4
<Hyphessobrycon columbianus; a fin-nipping species... could be nipping the Neons, Guppies, etc.>
Bleeding Heart Tetra - 4
Corys - 5
Peacock Gudgeon - 1
L183 Starry Night Pleco - 1
Clown Pleco - 1
Fancy Guppies (male) - 3
Maybe I am being too cautious. I appreciate any input you could give me.
<Cheers, Neale.>

Cory cat question, hlth. mostly 7/27/09
First here the specifics of my tank:
nitrates/nitrites= 0
pH= 7.2-7.4
Temp- about 70-75 degrees F
<While this low-end range is idea for most (though not quite all) Corydoras catfish, it is a bit low for most other tropical fish, so do be careful what you add. Platies, Otocinclus and Cherry Shrimps should thrive in cool, well-oxygenated water, but Bettas, not so much.>
Light- fluorescent for 12 hours a day total (timer is set for 2 hours on then a half hour off during the day so the bulb and ac/dc converter don't over-heat)
Plants- 6 small, broad leafed plants and driftwood
Size- 12 gallons
<Bit on the small side for adult Corydoras and Platies.>
Inhabitants: 1 male Betta, 3 female platy's, 1 small otty, 3 spotted Cory cats, a couple of cherry shrimp (I just noticed some babies too), more snails then I would like (and are constantly removing!)
<Keep your tank clean. Snails convert waste, particularly uneaten food and dying plants, into baby snails. The cleaner the tank, the less the snails can breed. Adding something like Clea helena (the Assassin or Snail-eating Snail) also works wonders. They're widely sold in England, and perhaps elsewhere.>
water change: 25% every 7-10 days, I treat the water with a water conditioner before adding it and match the temperature.
All fish have been together for about 2 months and get along very well (no biting or chasing, no one has damaged fins, all are active and eat well)
I had a 4th Cory who about a month ago (1 month after I got it) became sick. I first noticed it would stay by itself, it lost weight, and its tail fin was slightly clamped and a little red at the base. I treated the tank with an anti-fungus agent containing Nitrofurazone, Furazolidone, and potassium dichromate as per the directions.
<Why did you treat for Fungus? Were there symptoms of fungal infection?
Just to recap: Fungus looks like tufts of short white threads. It's often compared to cotton wool. If you don't see this symptom, then Fungus isn't likely, and use of anti-fungal medications is a waste. Do always remember medicines are poisons! Overuse, or careless use, will cause harm.>
There was no change in the fish and he/she became increasingly lethargic and started having labored breathing (the tail was still clamped and the redness was spreading from the base towards the tip of the fin). I retreated the tank after 4 days and a water change (as per the product's directions) and there was still no change in the fish and all the other fish showed no symptoms. Finally, after about a week the fish died. The tail had white fuzz on it, it was very red and there was some marked degeneration when I found him in the morning.
<Now, white fuzz, which can be Fungus, will often appear when a fish has died, or is close to death. Fungus is part of the natural, healthy ecosystem in your tank. Among other things, it breaks down fish faeces into the chemicals the biological filter can process. But the flip side is that a moribund or dead fish is every bit as delicious to fungi as a lump of fish faecal material. The fungi just eat whatever they can find. In your case, this Corydoras may well have been sick because of something else, and the fungus was just an opportunist that jumped onto the fish as it was dying.>
I figured this was just a weak fish but then 3-4 days ago (its been about a month since the above fish died) another Cory has the same symptoms and all my other fish look completely healthy (I haven't added any new plants or fish in the interim). I tried the same fungus killer and it hasn't made a difference. The fish is getting worse and I doubt he'll be alive by tomorrow morning but I am worried that this will keep happening to my other fish and I do not know how to treat the water.
<First of all, what is the water quality? Corydoras must have clean water, so 0 ammonia and 0 nitrite are critical. Secondly, the water must have too-extreme a set of chemistry parameters. Aim for pH of 6 to 8, 5-20 degrees dH. It doesn't matter precisely what the values are, just that they are stable from week to week. Corydoras are otherwise very hardy, but in tanks with poor filtration they frequently become the first fish to get sick. This is because the bottom of the tank is the bit with the least oxygen and the worst water quality.>
I did a massive water change after the first fish died.
<Don't change more than 25% in any one day, unless you are 100% sure the new water has similar temperature, pH, and hardness.>
I was thinking of treating the whole tank with an Ick-clear product to cover my bases if its a more resistant fungus
<No, no, no... medication doesn't work this way. All you're doing is randomly adding one medicine after another. Instead, identify the disease.
Check water chemistry, water quality, and water temperature to factor out environmental issues (which cause some 90% of the fish diseases aquarists encounter). Then, if you are sure the disease requires medication, select the right medication for the job, and use precisely as instructed. Do not use more than one medication at a time, and always remove carbon (if you use it) while medicating. Don't do water changes while the course of medication is being used (this applies to those that require several doses across several days). When you're done, do two or three 25% water changes across the next couple of days to flush out any remaining medication *before* adding any new medications (or additional courses of the medication used first time around).>
Other than that I do not have any ideas, please help!
<Cheers, Neale.>
As a side note, is there any safe product to combat snails that will not kill my shrimp Also, I don't plan on replacing the 2 fish that died because I think the tank was slightly over crowded even though the water was within healthy parameters.
<See above. Never, ever add anti-snail medications to an aquarium. They do far more harm than good. Cheers, Neale.>

Albino Catfish?? 6/26/09
I have what I think is an Albino catfish, it hasn't been well for the last 3 weeks now.
<Do you mean an albino Corydoras or an albino Ancistrus Bristlenose catfish?>
For the first week it was "tornadoing" and spinning in circles, couldn't swim straight if he tried.
<Often a sign water quality is seriously bad: check the pH is stable, somewhere between 6 and 8 but not varying much; also check that nitrite level is 0 and ammonia level is 0. Can also occur when water that is too cold (barely above freezing) is added to a tropical tank, or when the water contains some toxin that hasn't be treated with an appropriate water conditioner, such as chlorine, copper or ammonia.>
It didn't seem right to me but I was told this was the nature of the fish to be a little crazy.
Now for about the last 2 weeks it hasn't moved from the bottom of the tank laying on its side.
It is still breathing but doesn't seem able to really move.
<Outlook is grim.>
It seems completely normal in that it isn't bloated or discolored at all, it seems its just gone lame?
<More likely you're doing something wrong (or rather, not doing something right) in terms of maintenance. Let's assume this is a Corydoras catfish.
These are schooling fish, and it's cruel to keep them in groups of less than 5 specimens. They need a reasonable amount of space, 20 gallons or more for a group of 5. They need warmth, but not too much, around 24 C/75 F being ideal. The water should be clean, 0 ammonia and 0 nitrite, and the filter should be working briskly enough that there's a good strong current.
The water used in the tank should have a hardness between 5-20 degrees dH, pH 6-8. You shouldn't be using water from a domestic water softener or heaven forbid de-ionised water by itself. All water should be treated with a dechlorinator before use.>
Any information you can give me would be greatly appreciated.
<Need more information than you've offered, to be honest, so can't help much at all than to suggest what you might be doing wrong.>
Kind Regards,
<Cheers, Neale.>


Strange nub near gills 05/21/09
I have an established 30 gallon tank that I recently added 3 Sterba's Corys to. They all seem happy and healthy (eating, bumbling and foraging), though the largest one has a strange orange nub growing near his gills on one side (same color as his fins). I don't have a quarantine tank so I'm hoping it's not something contagious, and if it's something that can be cleared up I want take care of it before it progresses. I don't know of any parasites that would show up as that bright orange color. The gill cover doesn't appear distended, and otherwise has normal coloration. Water parameters and ph are normal, substrate is fine gravel, and there are plenty of hiding places among the plants and logs. They seem to be
adjusting with minimal stress, and I'd like to see them remain healthy and happy. Do you have any suggestions as to what might be causing this nub?
Could it just be some sort of benign tumor, or should I be treating the tank for something else? I didn't find any specific information online, and I'm hoping you might have some insight.
Thanks for your help,
<Hello Eve. I've not come across this problem with Corydoras, and it isn't one for which I can offer much useful help. If the thing is clearly a cyst or benign tumour, i.e., looks like swelling rather than an attached parasite, then there isn't much you can do. If the animal is otherwise healthy, then you can ignore it. It certainly can't be cured (removed) without veterinarian help. A more serious problem is if the thing is a Microsporidean parasite such as Glugea, which I'm dealing with at the moment with some Sticklebacks. This looks like a swelling divided up into a few small "bubbles", and is very distinctive; see for example the advanced case show here: http://www.cob.lu.se/microsporidia/proj_descr.html
Most parasites require an intermediate host not present in aquaria, so do not spread, but Glugea, like Ick, can spread from one fish to another. As such, it is best to remove infected fish, and ideally euthanise them (described elsewhere on WWM).
Cheers, Neale.>


Sterbai Corydoras with White Lump on Nose 4/14/2009
Hi There
Two days ago I discovered that two of my five Sterbai Corydoras had lost their barbells and both have a white lump on the tip of their nose. The lump appears to be solid, see attached pictures.
I've removed them from the community tank and put them into my 25L holding tank. As per the LFS (here in Australia) I have begun treatment with Tri-Sulfa tablets. I've also added an airstone to the tank, in case they need extra oxygen. The other Corys and community fish appear to be fine.
Prior to the Corys getting sick, my community tank details are:
1. Water parameters
Temp: 28C
PH: 6.8
Ammonia: 0
Nitrites: 0
Nitrates: 5
2. Tank set up
Size: L 36' (92cm) X W 14' (36cm) x D 19' (50cm)
Substrate: As seen in above pic, small round smooth gravel
Filtration: Aquaclear 50 (HOB)
Furnishings: 2 logs (aquarium decoration bought at LFS), 2 slate rocks, a terracotta pot, a terracotta plate, 1 large piece of driftwood, 3 Amazon sword plants
Tankmates: 2 Bolivian Rams, 1 SAE, 6 Dwarf Neon Rainbows, 6 Neon Tetras, 9 Ember Tetras
Tank has been established for 11 months.
Does anyone on the Crew know what this is, and have I begun the right treatment?
Thank you in advance for any advice on this matter.
<Deanna, the treatment is very simple. Take out the gravel; put in smooth (not sharp!) silica sand or an aquarium sand expressly suitable for burrowing fish (many aren't, e.g., Tahitian Moon Sand).
What you are describing is extremely common. All that happens is that the Corydoras burrow into the gravel, or try to at least, and they damage their snouts. Bacterial infections set in, and the whiskers rot away. Corydoras shouldn't be kept in tanks with gravel, though a lot of people do so (and yes, they all have Corydoras with missing whiskers). Cheers, Neale.>

Re: Sterbai Corydoras with White Lump on Nose - Follow Up Question 4/14/2009
Thanks for your prompt response Neale. The choice of substrate did cross my mind, and I will change over ASAP. Should I continue with the Triple Sulfa treatment in the quarantine tank because they still have a lump on their nose, or can I move them back to the main tank?
<Hello Deanna. By all means carry on treating against Finrot, but in all likelihood these fish will get better by themselves. So finish the course you've started, but once done, simply wait for the Catfish to heal. Cheers, Neale.>


Dying Cory cats Hello all, been a while since I've emailed. Thanks for your continued advice. I have a problem with my Julii Corys that has me puzzled. I have a very well established 29 gal tank that I run RO water in since my local water is extremely hard. I have several species of Corys including, until last week, 9 false Julii Corys. The tank is well planted and water conditions are excellent albeit a bit on the acidic side. This never has been a problem and the fish have thrived. However last week I lost two Corys unexpectedly. They each went from perfect to dead very rapidly. I've never seen such healthy-looking dead fish. Similar behavior for both: hovering at the water line making bubbles to exhaustion, then losing balance, then gasping, then dead within a matter of a couple hours. This morning I've noticed a third Cory starting the same pattern. I've done two 50% water changes and added an additional water stone thinking perhaps the O2 content was low given the gasping. I've added some pH stabilizer each day over the last few so now I'm around 6.8. (I usually add some aquarium salt during water changes to augment the RO). Thinking perhaps swim bladder problems but can't imagine why multiple fish affected simultaneously. Any thoughts or suggestions? Appreciate you, Dean <Dean, do please check circulation in the tank. Corydoras are extremely sensitive to poor circulation. While they do gulp air if they need to, they are essentially fish that rely on dissolved oxygen. If you have, for example, a hang-on-the-back filter it is entirely possible that water circulation from the bottom of the tank (where the catfish live) to the top of the tank (where oxygen gets in) is poor. The fact the cats are spending time close to the surface suggests that this is the problem. Also check the substrate is clean (it should be given a bit of a rake through every couple of months, at least) and that the pH is stable between water changes. Another misconception with Corydoras is that they tolerate/prefer warm water. They most certainly do not! The maximum temperature for most species is around 25 C (77 F) if you want them to do well. Ideally, slightly cooler, around 22-24 C (72-75 F). Finally, do spend some time reviewing the basics. If you're adding salt to a freshwater aquarium, you're doing something considered (at best) obsolete and at worst harmful for the last few decades! There's no need to add salt. If you are using RO water, that should only be a portion of the water added to the tank. Unless you are keeping something very specific that needs super-soft water, then a 50/50 mix of RO with hard (non-softened) tap water is perfect. That'll give you a hardness around 10-12 degrees dH, pH 7.5, an absolutely ideal level for Corydoras and a wide range of community tropicals. Very soft water causes all kinds of problems, and for the vast majority of aquarists there are more risks associated with very soft water than benefits. Moreover, adding salt -- by itself at least -- to RO water, and assuming that makes it water acceptable for keeping freshwater fish is not correct. By all means use it dilute the hardness of tap water 50/50, but never, ever keep fish in a 100% RO water, even if you're adding a little salt. Cheers, Neale.>
Re: dying Cory cats
Thanks for the advice Neale, fish seem to be doing well. Appreciate you. <Glad the fish are well, and thanks for the kind words. Cheers, Neale.>

Have irreparably harmed my Cory? 3-5-09 Hi. I moved some slate from my 20 gallon to my 40 gallon tank last night. Later on, I noticed my 3 Peppered Corydoras were not moving and my smallest was laying on his side. My other 3 Albino Corydoras along with Platy and 2 fry seemed okay. Am and Nitrites 0. I did 40 percent water change prior to bed. Upon waking this morning, all Corydoras were listless and I thought the smallest one was dead at the top stuck in a floating plant. Am and nitrite still 0. I scooped him out and tossed a good foot into a bucket. He wasn't dead. I immediately tossed him back in the tank (so I thought). I went and prepared some water for another change, came back and found him on the side of the tank ( still breathing). I panicked and put him in a bucket with some tank water and a couple drops of Methylene blue and an airstone while I changed the water and added a Eheim liberty 200 filter to further help conditions in the main tank. All the other Corydoras have perked up. The other is back in the tank floating at the top on it's side, it did go back down to the bottom for a few minutes and now it's back up top, barely breathing. I don't want to make the mistake of considering it dead again, but I don't want it to suffer. Should I euthanize this fish? Wait a bit? I feel like I'm in a fish horror story and I'm the bad guy which I guess I am. :( Gina <Hi Gina. Adding Methylene Blue without good reason is never a good idea. If you see unhappy fish, it's almost always an environmental issue, possibly poisoning. The latter is often a problem if you've been doing painting or anything else that releases fumes into the air. Because Corydoras are air-breathers, they're particularly prone to this type of poisoning. Assuming water quality is good, I'd check the temperature, pH, hardness, and that water circulation is adequate (i.e., the filter isn't running slow), and that there's nothing rotting in the tank that could be using up oxygen. Change 50% of the water now, and 50% early the next morning. Essentially try and flush through lots of clean water. Have you added anything new? Plants? Fish? If so, consider Ick and Velvet as possible stowaways, and act accordingly. Corydoras are pretty robust, and I'd not count them out too soon, but do observe closely for the next few hours. A photo would help us identify problems. Cheers, Neale.>

Re: Have irreparably harmed my Cory? 3-5-09-09-09 Hi Neale. The only thing I did was caulk up some holes in my wall a few feet from the tank the Cory is in. I don't know if that factors in. <Hmm... certainly possible if any types of solvent were involved. By default, when doing home repairs nearby your fish, keep windows wide open and a good strong flow of air through the room. Obviously moving the fish to another room is even better, but not always possible.> I've attached a picture, he seems worse today (not attempting to move away). I've done the water changes as instructed and all other fish in that tank seem okay. I did add some rock to the Cory's tank that I had bought for a redo on my 10 gallon tank that was left over. <What kind of rock? Some rocks are safe in fish tanks, but many aren't.> It was in the 10 gallon for a few hours before I moved it. <OK.> I mention the 10 gallon (in a different room) because I woke to find my six new Kuhli Loaches (had about 3 days) were all dead. <Suspect these were in bad shape before purchase: they are VERY underweight. If you look at them, their heads are bigger and thicker than their bodies. Since the skull doesn't shrink with starvation, but the muscles around the body do, this is usually a sign the fish is starving. In fact a healthy Kuhli will have a chunky body and usually a distinct "shoulder" behind the head where its body is obviously more robust that the head. So in this case, you may have come home with weak fish, making things difficult.> I had recently redid the tank for them (rocks, sand). I added a Eheim Aquaball and kept the sponge filter in the tank. When I came home from work last night, one was floating at the top in a plant (usually stays on bottom during day) but eventually moved down. I thought it was because I had put my Betta in with them and he bullied him. So I removed the Betta. <Bettas and Kuhlis normally get along fine.> Then at bedtime, turned off the lights, threw in an algae wafer (new bag bought last night) and checked on them before bed and they were swimming and doing figure eights, very active. Then all dead this morning. Am 0 Nitrites 0 Nitrates 20 PH 6. I've been struggling with low PH and had removed all driftwood from my tanks and all have had several water changes, the PH doesn't seem to be moving. <A sudden pH change certainly can kill fish. Is the pH 6 all the time? Or does it go up and down? If you have a pH of 6, it's likely you have soft water. I'd recommend fixing that by raising the carbonate hardness. Various ways to do that: commercial pH buffers (7.0 would be ideal); adding a small amount of crushed coral to the filter; or adding a 1/4th to 1/2 dose of Rift Valley cichlid salt mix (not normal salt!) to each bucket of water. Do see here: http://www.wetwebmedia.com/FWsubwebindex/fwsoftness.htm Oh, and do make sure you aren't using water from a domestic water softener; that's very bad for fish. Only use drinking-quality water.> I just bought and set up the 40 gallon tank ( I don't know if you remember our conversation last week ) and now I'm thinking of chucking it all except the Betta and a 5 gallon. I don't understand what happened the last couple of days at all and don't want to do anything until I do. <I'm not 100% clear what's going on, though I suspect the sick Corydoras and the dead Kuhli loaches are separate issues. Now, do remember that the bigger the tank, the more stable it will be, so keeping a 40 gallon tank will be miles easier than a 5 gallon, all else being equal. So don't get too disheartened! But please, go slowly, and do feel free to ask as many questions as you want. I think once you understand the issues behind soft water and pH changes, you'll be able to see the dangers you need to avoid. Cheers, Neale.>

Re: Have irreparably harmed my Cory? (RMF, would appreciate input)<<Ok>> 3/9/09 Hi Neale. Thanks for all your help. <Most welcome.> The pH in my 20 gallon tank that has been running for 2.5 months is at 6. I added Seachem's Neutral Regulator with a 25 % water change Sat night and again Sun Morning. It doesn't seem to budge the pH. <Hmm... this is a very low pH for a community tank. While not in itself a disaster provided you stick with soft water fish only, it would be the wrong place to keep hard water fish like livebearers. My gut feeling would be that if you can't beat 'em, join 'em. Choose only fish that will enjoy these conditions.> I'm reluctant to add it directly to the tank as I wanted to raise the pH slowly. <Correct. You should never add these chemicals directly to the tank. Instead, add them to buckets of water. Alter the water in the bucket, and then use it to replace a bucket of old water in the tank. Over the weeks, the aquarium will gradually shift from whatever the conditions are in the aquarium to the conditions you are creating in each bucket of new water.> With the water changes, the pH will move up towards 6.4, but within a few hours drops back to 6 (the lowest my test goes). <Implies a variety of things, though most likely a combination of high stocking (lowers pH via organic acids, nitrate, etc) and lack of carbonate hardness in the water (nothing to inhibit pH decline). Certain materials, notably bogwood, will also lower pH.> I get the same readings and results in the 5 gallon tank that has the Betta. <OK, does sound as if you have very soft water. This is tap water, right? Not from a domestic water softener? You should never use water from the latter.> I purchased one of those test strips for alkalinity. <OK.> Currently in the 20 gallon (which houses 3 Platies, 1 fry, 6 Corydoras (the sick one is swimming around and looking for food a bit now) : pH 6 Hardness 120 (which reads as moderate not soft? Also, I do have build-up around my faucets) <<This could be salts, not of Ca, Mg... not contributing to hardness... RMF>> Alkalinity 0 Nitrite and Nitrate 0 Ammonia 0 My tap water comes out (tested from inside and outside sources, tested immediately after drawn and then after aerated for 24 hours) pH 8 Hardness 120 Alkalinity 120 (sometimes looks more like 180) Ammonia 2 + <<?!. RMF>> Currently in the 40 gallon which was filled with conditioned water, pH 8, 4-5 days ago and has been running with Eheim filtration with temperature set at 80 degrees. The Alkalinity in the 4 days has dropped from 120 (180?) to 80. pH from 8 to 7.6. I added a full dose of Seachem's Regulator on Saturday to this tank. <I'm getting a déjà vu feeling here! For one thing, you're using strips, and these seem to be less reliable than liquid test kits, so if possible have your local aquarium shop test some water and compare it to the results you get. But secondly, there seems to be a thing with the water supplied to some (American?) households where the water chemistry rapidly changes of its own volition within a few days. For whatever reason, it isn't something I've come across in the UK, so can't speak about from personal experience. Essentially it means that there's a combination of additives and minerals in the water that over a few days change sufficiently that water chemistry alters dramatically. Take a look here: http://www.wetwebmedia.com/FWSubWebindex/fwhardnessfaqs.htm Go specifically to the thread "pH/Ammonia Issue (RMF, never come across this, any ideas?)" and you'll see than Bob and I went over and over a similar issue with another a fishkeeper.> <<I have re-read... and have encountered such issues, vacillating GH, KH in tap/mains water supplies... As stated in the cited string above, there are municipalities that at times will run more of a few types of mainly "flocculants" (though other chemicals can/do have this and other "anomalous" effects)... And there are many cases of "bad readings", particularly for strip-type tests... and other endogenous factors can certainly cause wide and rapid shifts in hardness and pH... as is gone over... RMF>> I've read that certain conditioners for chlorine, Chloramine and ammonia will pose false positives for ammonia depending on the test kit used. <Correct. Test the tap water prior to adding anything. Any traces of ammonia will be dealt with via your additives, so shouldn't be an issue.> With Kordon's AmQuel as I can get the ammonia down to 0 for water changes (using twice the dosage amount, but reads for 1 ppm removal, since my tap comes out at 2 ppm, I'm assuming this is correct?). <Can't do any harm.> With Seachem's product, which says it treats for all the same, I can't get the level down to 0, in fact it doesn't budge the ammonia at all. <Your ammonia test kit will detect "false positives" from certain other chemicals, such as Chloramine and apparently Nessler's reagent.> Nor does it seem to adjust the pH based on my drip test (neither on water drawn and conditioned and tested immediately nor tested 24 hours later after being aerated). Another conditioner I tried this weekend will drop the ammonia to .25, but no less, no matter how much I add. Am I over dosing the conditioner? Am I correct to not add any water to my tank unless it reads 0 for ammonia? <<Yes! Best to treat, store "new" water outside the system... for a week if you can. RMF>> Can you best advice on how to stabilize my pH from here? Or ideas on to the cause and/or how to further test to determine what is going on? I've recently upgraded all filtration and moved the biological filtration to the new. However, it seems useless since my pH is so low. <OK, here would be my advice. Put the strip test kit to one side for now. I'm assuming it's an all-in-one strip, right? Let's assume these are mislead/unreliable when used with your tap water. Leave them for checking nitrite/nitrate levels at which they'll be fine and dandy. Good enough for making sure your water changes and filtration are doing their thing! Buy a carbonate hardness test kit and a pH test kit. These are the two critical ones for water chemistry. The general hardness test kit, though it sounds useful, actually has somewhat limited usefulness despite being "general". It doesn't really tell you anything about the ability of water to resist pH changes; only how much non-carbonate "stuff" is in the water. Since these minerals have near-zero impact on pH buffering, this isn't informative. Now, your carbonate hardness kit will test specifically for the carbonate and bicarbonate content of the water, and THIS is the stuff that keeps pH from changing. The aim for most freshwater fishkeeping is get a carbonate hardness of around 5 degrees dH (about 90 mg/l calcium carbonate equivalent). This amount should buffer against any reasonable amount of acidification between weekly water changes. If you find you don't have this amount of carbonate hardness, you'll need to add some to each new bucket of water. A good Malawi Cichlid salt mix will do the trick, though obviously there's no need to use the full dose. The usual ratio is: 1 teaspoon baking soda (sodium bicarbonate) 1 tablespoon Epsom salt (magnesium sulfate) 1 teaspoon marine salt mix (sodium chloride + trace elements) For a Malawi aquarium you'd add this to each 5 gallons/20 litres, but since we likely won't need nearly so much, try using one-fourth the amount to begin with, and if that doesn't work, one-half. So initially, 1/4th a teaspoon of baking soda, 1/4th tablespoon of Epsom salt, 1/4th teaspoon marine salt mix. This is clearly not an expensive way to go! But it works really well, and should fix the pH at around 7.5 plus or minus a little, and get you a carbonate hardness around the level we want. General hardness will be somewhere around 10 degrees dH, but it really doesn't matter that much. Add these salts to buckets of water prior to use, and ideally, leave the water overnight and then test the water chemistry (pH, carbonate hardness) again the first few times, just to see how things pan out. With luck, the Malawi mix will compensate for any funniness in the water as supplied by your water company. Problem solved.> The tanks have river rock, sand, slate, gravel, but nothing that I haven't bought at a LFS. <Cool.> Thanks again for any insight or instruction you can provide. Gina <Hope this helps, Neale.> <<I do agree with your "all fits" advice above... Starting with most any/all source water, the simple mix/addition should serve to bolster hardness, fix pH well enough... RMF>>

Re: Have irreparably harmed my Cory? (RMF, would appreciate input) 3/10/09
Thanks, both of you.
<Most welcome.>
I've treated 5 gallons of tap water with Amquel and 1/4 tsp of each baking soda, Epsom salt and marine salt. I'll let it sit overnight with an airstone before I do a water change.
<Quarter TABLESPOON of Epsom salt! Not teaspoon. No big deal this time around, but try and get it right next time, eh? Oh, by the way, one tablespoon is three teaspoons, so a quarter tablespoon would be 3/4ths of a teaspoon.>
I got a carbonate hardness test as well. I already had liquid tests for pH and all the others. Although the numbers are a bit different, it seems to show the same trend as the strip test.
The 20 and 5 gallon tanks register a pH of 6, 0 mg/l.
<Low; biological filtration operates best around 7.5-8, and below 6 stops altogether. So unless there's a darn good reason, a pH of 7 or slightly above is the ideal for community tanks.>
The 40 gallon tank that was conditioned with Amquel and has been running fishless at 80 degrees with a pinch of food added daily, registers 50 mg/l and a pH of 7.2. This is after 5 days. My tap comes out 90 mg/l and a pH of 8. I have had a bucket of untouched tap water running with an airstone for close to two days and it still has the same readings. So I'm assuming around 4/5 days my carbonate hardness drops by half? I'll guess I'll keep testing the tap water and 40 gallon tank to see how fast it continues to drop.
<If you add the carbonate hardness "recipe" suggested, my prediction will be that water chemistry in terms of pH will remain essentially stable between water changes. The higher the carbonate hardness, the less pH will drop. Hard, alkaline water (like in a hard freshwater aquarium) basically doesn't change at all, or if it does, by tiny amounts. See how the one-fourth dosage I've recommended works out; if it doesn't work, up the dosages to one-half dosages per bucket of water. Even at full dosage, it's would be ideal for things like livebearers, though soft water fish such as tetras might complain.>
I'm assuming I won't see a jump in the pH or carbonate hardness with the Cichlid mix overnight ( in the treated change water) as it takes several days for it to drop.
<Correct. And with increasing carbonate hardness, the rate at which pH drops will slow down.>
Does that mean, it might be several days before I see a change in my 20 gallon tank?
Is a 20% water change with the new mix, every day, too quick a change?
Should I go slower than that?
<This should be fine.>
Also, Bob, had put a ?! next to my tap water ammonia reading of 2+.
<This is for your tap water, right? Before treated with dechlorinator? The _maximum_ allowable level in drinking water is 0.5 mg/l, in the United Kingdom at least. Ammonia usually gets into drinking water via things like agricultural run-off. Do check with your water supplier what the ammonia content of the water supplied to you should be, and ask whether this reading is normal. There could be a problem. If you're detecting the ammonia AFTER adding dechlorinator, you're probably detecting Chloramine after treatment with dechlorinator. Provided the dechlorinator treats Chloramine, you can ignore this "false positive" reading for ammonia.>
It's steadily at 2. Is this abnormal?
<Yes; check with your water supplier.>
I shower in the stuff and my dogs drink it.
<Ammonia isn't especially toxic to humans at low doses (our bodies produce the stuff all the time) but it isn't normal to get this amount in drinking water. If you add water with ammonia at 2.0 mg/l to the aquarium, you're basically dumping a lot of pollution in there. While the filter will fix that problem reasonably quickly, for a short while at least the fish will be exposed to a serious toxin.>
Eventually I would like to store water a week ahead as suggested, I tried it at the beginning of all this but after week the tap water still registered ammonia at 2. But at this point, I've read so much, I feel like I have too much information and not enough understanding.
<<Ahh! A beginning for enlightenment. RMF>>
<The addition of carbonate hardness to each batch of water should make the water chemistry problem go away. Trust me on this. As for the ammonia, that's a weird one. Some products such as Kordon AmQuel will remove ammonia from tap water, making it safe to use. Do see here:
Once your water is hardened and then treated for chlorine, Chloramine and ammonia, it should be ready to use. I can't see any further problems with your fishkeeping, and hope it will be a LOT SIMPLER after this.>
I'll keep you updated on if this works for my system. If it does (fingers crossed) does this mean I should eliminate my Corydoras from my tanks since I am using a salt mixture to steady the chemistry? :(
<Nope. The amount of carbonate hardness is low enough not to bother Corydoras, and the salinity trivially slow. To put this in context, seawater has 35 grammes per litre salt, which is almost 6 teaspoons per litre, or about 22 teaspoons per US gallon. The one-quarter teaspoon is as nothing by comparison.>
Thanks again,
<Cheers, Neale>

My Cory Has No Tail -10/26/08 I just realized that one of my Corys has no tail. <Significant...> Will it grow back? <Depends on how deep the damage has gone.> The poor thing can't swim. I feel horrible for him. I don't know how or when he lost it. I tried putting food right in front of him so he could eat, but he didn't go after it. Is there anything I can do for him? <Mary, it sounds like he lost it for one of two reasons: pH or nitrogenous waste troubles. Both would explain the loss of fin and sluggishness- have you recently done water changes, or tested pH, NH3, NO2, NO3? if any of these are out of line, do some 25% water changes a couple times daily STAT...with time and good water quality, hopefully the fish will recover.> Thank you for your help. Mary <No trouble. Benjamin>
Re: My Cory Has No Tail - 10/26/08
Hi Benjamin, First, thank you for your reply and suggestions. I just recently had to treat for Ich. (Jungle Ich Treatment did first treatment about a week and a half ago and then again two days ago with a 25% water change before the second treatment.) I had added some new fish to my tank and got a horrible outbreak of Ich. I have 6 Corys, including my little tailless one, and one black Sailfin Molly left in my tank - it is a 36 gallon tank. (I lost two speckled Mollies and two Swordtails from the Ich - all 4 fish were females.) I did do a water check with a master test kit and all levels are fine. Do you think the tail loss could be from the Ich meds? I have set up a hospital tank (3 gallon) in case I need to medicate. Thank you again! Mary <Hello Mary. The Ick medication wouldn't have caused the loss of a fish's tail. Let's be quite clear on something: Ick should never, ever be a cause of death among fish. It is very easy to cure, and because the symptoms are so obvious, it's easy to diagnose. In a tank with livebearers (guppies, swordtails, mollies and platies) raising the temperature to 28-30 C and adding 2-3 teaspoons of tonic salt per gallon will stop the problem within days, and after a couple of weeks the fish will be perfectly healthy. Livebearers all tolerate salt extremely well, and in the short term even Corydoras will put up with it. There are also numerous off-the-shelf medications, though most of these contain copper and formalin, and some fish, notably loaches, react badly to them. Anyway, the only reason Ick medication "fails" is because the user didn't take the carbon out of the filter. I'm dead set against the use of carbon in most freshwater tanks, not least of all because of this easy mistake. If your fish die despite treating for Ick, then two things are going on: either you left it too late to treat them, or else the Ick is merely a symptom of stress caused by something much more serious, for example poor water quality or the wrong water chemistry. I mention this because people often make mistakes with Swordtails and Mollies. Swordtails are riverine fish that require cool (around 23-25 C) water with lots of current and oxygen. A small aquarium (anything less than 30 gallons) isn't acceptable, and even in the right tank you need perfect water quality and generous filtration. If the fish aren't having to work hard to swim against the current -- you're not providing your Swordtails with enough water current. I'd recommend a filter offering upwards of 6 times the volume of the tank in turnover per hour. Don't waste your time with those stupid hang-on-the-back filters, but instead use a decent internal or better yet external canister filter that will really move the water about. External canisters are ideal because they suck water in from one end of the tank and push it out the other, really getting the circulation going. Next up, Mollies. These are, despite advertisement to the contrary, not community tank fish. Yes, they're beautiful and peaceful, but they need brackish water to do well, at least when kept by the average, non-expert aquarist. The problem is that Mollies are hugely intolerant of pH changes, nitrite and nitrate. Adding marine salt mix (not "tonic salt" or "aquarium salt") provides bicarbonate/carbonate salts that buffer pH and sodium chloride that detoxifies nitrite and nitrate. http://www.wetwebmedia.com/FWSubWebIndex/mollies.htm So despite Mollies being mostly freshwater fish in the wild (though they are also found in estuaries and even the sea) in aquaria they are simply best treated as brackish water fish. For this reason, based on my 25+ years of experience in freshwater fishkeeping and in depth study of brackish water fish, I routinely tell people to keep Mollies in their own tank away from freshwater fish such as Corydoras. Some hardy Corydoras species may tolerate very low salinity (say, 3-4 grammes per litre) but it won't do them any good. Oddly enough, the catfish Hoplosternum littorale is a close relative of the Corydoras and naturally occurs in brackish water, and as such makes an ideal companion for Mollies. Mollies can also be kept very well in true brackish water communities, and as such mix great with other livebearers (which generally tolerate salt well) as well as a wide variety of small to medium sized brackish water fish such as Knight Gobies, Glassfish, Limia, Halfbeaks, etc. I hope this clarifies things. Cheers, Neale.>

Corydoras deaths 10/6/08
Hi Crew,
I have to say that I love your site, every day after work I check out the new FAQs. You've saved me from all sorts of horrible LFS advice.
<Glad we could help.>
I have a 75 gallon planted tank which has been running for about 8 months now. I have 432 watts of T-5 lights sitting over this but the heat from them does not change the temperature of the tank noticeably, it sits at 26 C day and night. I tend to change out around 10% of the water every week. I do have an Eheim canister filter on here but it's wholly underrated for this tank. Only does 116 gallons per hour according to the box, likely much less since it's got ceramic tubes and a filter pad inside. It's mainly there just to keep the water slowly moving around.
<Would recommend beefing up the filtration a bit, if only to keep up with the growth of your fish and ensure adequate water circulation. To be sure, vigourous plant growth can have a strong filtration effect, but you don't want to rely on it.>
Everything I test for seems good: pH is 7.5, hardness is about 250 GH, Ammonia and Nitrite are at 0, Nitrate barely registers, maybe 5ppm.
<All sounds great.>
This is with most of the Flourish line of fertilizers being added a couple of times a week based on their recommended dosages. Plus there are some fertilizer tabs buried under root feeding plants. Substrate is about 3' deep at the front, sloping up to 4' at the back. The bottom half is a mixture of Laterite and Seachem's Fluorite, while the top is cheap rounded gravel, 3-4mm in diameter. I have various Crypts, Swords, mosses, Hygros and Val.s as well as Java Fern, Water Lettuce, a couple Rubra lilies, a Lace plant, Banana Plants, Glossostigma, Riccia and a mystery Cabomba like plant. I am not currently adding CO2 but several of these plants have oxygen bubble streams coming from them in the afternoons anyway.
<Quite so; CO2 improves good tanks, but you can certainly make good tanks without CO2.>
Fish include one very happy Plecostomus, a Striped Raphael Catfish, 10 Otocinclus, 6 SAE, 2 Madagascar Rainbows, 3 Turquoise Rainbows, 2 Redtail Rainbows, 2 'Pink' Rainbows which are probably some hybrid, 6 Threadfin Rainbows, a bunch of Sunrise Platies and a dozen or so Mystery Snails. Nothing has been added for a month or more. The Threadfins court each other, the snails lay eggs and the Platies are always pregnant. The point of all this is that everything is growing and all fish are colourful, active and have nip free fins.
<Would be surprised if the Plec doesn't start causing problems eventually: at 45 cm in length and happy burrowers, they're pretty hard on plants.>
A week ago I added a small school of 10 Corydoras. I bought them as Peppered Corys but they look more like julii or trilineatus.
<Peppered Corydoras should be easily distinguished from C. julii or C. trilineatus simply by colour: Peppered Corydoras are grey, not black. C. julii and C. trilineatus are routinely confused in the hobby, but luckily can be kept in the same way.>
I should say that they were not quarantined first as I no longer have a quarantine tank. Every time I set one up I just end up with a nursery tank or another community tank after a while. At the LFS they seemed fine, no damage or dead fish to be seen. For the first day or so they followed each other around the tank ignoring and in turn being ignored by everybody else in the tank. On day two I found a dead one. On day three I found another dead one. I tried changing water and retested everything I could but found no problems. After six days I only had three left, one of which was floating around on its side. None of them, living or dead had any strange colours, swelling or damage that I could see. Even though I couldn't find any problems I thought that for so many to die in such a short time the problem must be environmental, so I took the 3 survivors and put them into a neglected 20 gallon tetra tank. This tank had much lower lighting and no Laterite or Fluorite. Everything but Nitrate registers the same as my 75 gallon, Nitrate is way up at 80 ppm. Far too high, I know. The day after I transferred them all 3 survivors were happily following each other around the tank. This was a couple of weeks ago and they're all still alive.
<Interesting. Corydoras are generally hardy animals, but they sometimes respond poorly to abrupt changes in water chemistry. My gut feeling is that you failed to acclimate them adequately; indeed, because of the way you maintain your tank, leaning on plant growth rather than filtration, the water chemistry (particularly pH) may vary strongly through the course of the day. Although a secondary issue, your water temperature is slightly higher than the 22-25 C preferred by most Corydoras.>
I've dug through your articles and FAQs but can't seem to find my problem.
I have read that these fish prefer lower hardness and temperature than I have but also that they can quickly adapt to a wide range of conditions.
<Correct; but like most fish, while they can be maintained across a range of conditions, they don't necessarily adjust to substantial changes rapidly. In other words, while anything between pH 6 to 8 is fine for maintaining a school of Corydoras, if you take a Corydoras from pH 8 and dump it in pH 6, you will likely kill it.>
This seems evident by the fact that 80 ppm of Nitrate didn't faze them.
While the water is probably 45 cm deep there are plenty of plants they can, and do, rest on.
<Ah, another good point. This is far too deep for Corydoras. Depending on the size of the catfish, you are best with under 30 cm for juveniles and up to 40 cm for adults. Anything above that is not compatible with their biology. In the wild they live in very shallow streams. Much better to go with Brochis spp. Corydoras are clumsy swimmers, and expecting them to perch on plants as they swim up to the tank is unreasonable. They have a "breath" reflex whereby they dash upwards to the surface and then back down again to the sand quicker than a flash, I suppose to avoid being snapped up by predators.>
None of them dashed for the surface all that often either. I didn't once spot anybody picking on these fish. Even after death, before the snails moved in anyway, all fins were pristine, gills were not reddened and the eyes were not cloudy.
While I vacuum the gravel every few days there is still plenty of detritus to pick through, plus I toss in a few Hikari Algae wafers every evening before lights out.
I see that sand is their preferred substrate but none of them had abbreviated or missing barbels, red bellies or anything I could see that would betray cuts from sharp rocks.
<Yes, sand is preferable, but clean gravel shouldn't be an issue.>
I apologise for this long email but I would really like to figure out what happened to these guys before I try adding any more. Any help you could give is much appreciated, thank you.
<Hope this helps, Neale.>

Albino Cory - red scrape marks on belly 8/12/08 Hi - I am completely new to this. I'm keeping my boyfriend's tank while he's out of the country. He's had the tank for a while now. It's a 20 gallon tank with Fluval filter. Population of tank: plant 2 rosy tetras 3 diamond tetras (2 new) 2 white fin tetras (new) 1 albino Cory cat 4 black mollies and some baby mollies <Please do consider upping the numbers of the schooling tetras, and the Corydoras certainly shouldn't be kept alone. Not a fan of mixing Mollies with Tetras.> I recently lost a diamond tetra and do not know why. I replaced it with 2 new diamond tetras. The existing one is very active, abnormally so. He now swims around a lot, in circles. Actually, all others seem to be very active as well. Not like before. <Diamond tetras are schooling fish, and on their own they do become neurotic, not to put too fine a point on it.> Water conditions; pH = between 7.4 and 7.6 KH = 30 (according to the conversion on the test kit = 1.68 dH GH = 120 (moderately hard according to test kit) Nitrite = 0 ammonia = 0 <OK. 30 degrees KH is NOT 1.68 degrees dH, so something is amiss there. Sounds like you have quite hard, basic water though. Fine for most fish.> Problem: albino Cory seems to have something that looks like red scrape marks on his belly. He swims to the top and seems to avoid lying down on his belly. Today I saw that he's laying on plant leaves on his side. What's wrong with the tank? Please help! <Usually when bottom-living fish show odd scars or blisters on their bodies, particularly their bellies and whiskers, it's to do with poor conditions. Specifically, they're in contact with the ground, and sharp gravel that damages them and bacteria on the gravel gets in causing an inflammation. Corydoras absolutely must never be kept in tanks with sharp gravel or sand produced as a by-product from glass manufacture (e.g., Tahitian Moon Sand). Those hideous painted (blue, red, etc.) gravels are usually very bad choices as well. You should use fine, smooth pea gravel, or better yet, smooth silica sand. Run your hands through the substrate. If it feels silky smooth, it's fine; if not, then it's not good for your catfish either. The substrate must be kept clean as well, at the very least by stirring it each time you do a water change and the muck that comes out being siphoned away. Do see here: http://www.wetwebmedia.com/fwsubwebindex/nicebottoms.htm > Diana PS - I did try searching the forum but couldn't really find a match for my issues. Thank you so much for your help. <Hope this helps, Neale.>

Albino Aeneus Cory with Unknown Affliction -- 8/8/8 Hello there. I was referred to your site by a friend and I hope you can help me out. I've been keeping/breeding/raising tropical aquarium fish for a few years, but have yet to come across anything like this. A couple months ago, I noticed one of my Albino Aeneus Cory females was getting very plump in the chest. Since this normally occurs prior to spawning, I thought nothing of it. However, the area kept getting larger, so I started monitoring her more closely. Since the group had not spawned recently, I attributed it to being egg-bound, or possibly constipated/having a blockage. I have upped my tank maintenance, fasted, and generally just made things as perfect as possible. Last weekend the group spawned, and she was right there with them, basket full of eggs and all.....she's not egg-bound. I have also seen her passing waste, so she's not constipated/blocked. Unfortunately the 'bubble belly' remains. I have seen her with the light behind, and her chest area honestly looks hollow, like a water bubble. I don't believe it's air as she has no issues with floating and I've never seen her fight to stay on the bottom. Other then the large chest which makes her rest funny, she is a typical Cory. Roots around in the sand, eats and schools with the others, darts to the surface for a gulp of air and general acts perfectly normal. I'm attaching two pictures of her in hopes you can help. Please note, she has always had the kink in her tail so that is not a new issue. Thank you in advance for any help/advise you can give. Worried Cory Mom :) <Unless someone has a better idea, I'd put this down to a tumour. Not uncommon among ornamental fish, and possibly related to either dietary or environmental inadequacies. Given these are albino fish, they're also likely to be inbred and genetically weak (if nothing else, albinism makes animals more vulnerable to damage from UV light, but that's not going to be a problem indoors). If the fish is otherwise healthy, I'd not worry overly much, but be prepared to painlessly destroy the fish if it shows signs of suffering. Cheers, Neale.>

Leopard Corys in trouble 6/6/08 Hi! Thanks in advance for the help and support. I have a new 180L tank which I cycled with the fishless cycling method. There are no ammonia, nitrites or nitrates (I guess my plants are using up the nitrates?). <Possibly, though you need VERY fast growing plants in GREAT ABUNDANCE for this to be true.> When everything was ready I bought six Corydoras julii, but I made a mistake. One of them was whiter than the others (from when he was at the store) and I thought he was just a little different. It turns out he was sick. He wouldn't team up with the others didn't have much of an appetite and eventually died after a week. <Oh dear.> The others seemed ok at first but now (4 days after) I see another one standing still, being pale and his eyes bulging out a little. <Hmm... do check water chemistry and water quality. Corydoras spp. are generally EXTREMELY robust, and assuming water conditions are adequate, they rarely get sick. Corydoras will ADAPT to almost any water chemistry, from very soft to very hard, pH 6 to pH 8. But what they don't like is sudden changes in water chemistry. So check the pH is stable. If you have rapid acidification, for example because your water is soft, then the catfish will get sick. Similarly, while Corydoras will tolerate poor water quality for short periods, in part because they can breathe air, they will eventually sicken if things don't improve. So double check the nitrite and/or ammonia concentrations.> I asked at the store where I bought them but their answers weren't very convincing. They said this happened because there isn't enough oxygen in my water. <Likely not an issue, because Corydoras can breathe air. While they don't like stagnant water, they can tolerate it for short periods. You will sometimes notice them swimming up to the surface to gulp air. Normally they do this every few minutes, but if you see them doing this very frequently, then you may have a problem.> However I have two filters one built in and a canister filter) and they seem powerful enough (the canister is 440l/h). <That's a turnover of about 2x the volume of your tank per hour. My recommendation for any normal community tank is a turnover of 4x the volume of the tank (i.e., 180 x 4 = 720 litres per hour). This is the minimum safe level to ensure all the water goes through the biological filter often enough all the ammonia and nitrite is removed.> They said I should buy an air pump but it just doesn't sound right. <I agree.> Anyway I asked at another store and they said it maybe some kind of parasite and gave me a medication called Hexamita to blend with their food, but there hasn't been much of a change. <Hexamita is a protozoan, a disease causing organism in fact. So double check the name of the medication.> My pH is 7.5 GH and KH both 9. I do two 40% water changes a week and I always use a water conditioner. My temp is around 25C. <All sounds well within the tolerances of Corydoras spp.> There is only one sick Cory right now (since the other one died) but I'm afraid the rest might get sick too. <Do review water chemistry/quality. Consider upgrading filtration. A photo of the sick fish might be helpful; when fish go white, it often implies external secondary infections, so treating with something against Finrot/Fungus might make sense. I use eSHa 2000 with success, but there are other medications out there you might use.> Sorry for the length of this question but I am very new at this. They are my first fish and I have done everything I can for them to be ok. I really really don't want to lose them and I just love their digging and dancing all around. <You are talking to a dedicated fan of the genus Corydoras! They are lovely fish, and handsomely repay extra care.> Thanks again Elisabeth <Cheers, Neale.>

Re: Leopard Corys in trouble 6/6/08 Hello! It's me again! I just wanted to say thanks for the quick answer. I think what you guys do is fantastic and has helped improve the lives of many fish all around the world (for example I am from Greece). And also a special thanks to Neale the Cory fan... <You're most welcome, and good luck with your fishes! Neale.>

Sick Cory cats? 4/8/08 Hi crew, hope all is well. I recently (Thursday) added 2 Corydoras Schwartz's to the 3 I already had in my 20 gallon freshwater tank. They came from the same small LFS and I was told they were the last of the group the first 3 came from, so I added them to the same tank (I know my first bad move). <Certainly can be...> I have had the others for over a month with no issues although I lost one the day after, but I truly think I was just inexperienced and did not acclimated correctly. So now I have 5 and they have been acting so cute, shoaling and everything! <Cool!> Last night I noticed a white looking area on one Cory's head which runs down behind the 'mask' to form a V when you look down from above. Actually a couple of them seems to have a 'V', but only one has the area on top as well. I am not sure at all if this is normal markings, as I don't remember it from before. <Does vary, but there are also look-alike species... often the problem with Corydoras.> I watch them every day and night. I love the way they appear to wag their tails like puppies. <Preaching to the converted... I enjoy keeping, breeding Corydoras very much. More sheer fun than any fancy-pants reef fish!> From all my reading last night and today I can't find anything like this so I am sending you some pictures hoping you can either tell me what to do ASAP, or put my mind at ease. Hopefully the latter. These pictures are the best I could get, these buggers are quick! <Too small really to tell... would prefer one decent sized photo around 400 px square rather than these.> I am pretty sure the one with the white on the head has been here for better than a month as he doesn't hide from me. The new ones run when I come up to the tank, while my others obviously know I am the food God and love to see me coming at dinner time. I did have some Algae issues from over feeding but I did a 50% water change and severely restricted light for a week or so, and I am still keeping short light times to discourage a reoccurrence. I was feeding 3 Hikari wafers a night! <My Corydoras love these too. Corydoras eat a lot of algae in the wild, and this aspect is often overlooked by fishkeepers.> But now I only feed 1 every other night with 1 little HBH shrimp pellet. I break all of these up into little pieces or they play tug of war with them! <I'd say one Hikari algae wafer (around the size of a small coin) per night for 5 catfish is about right. Maybe skip one night so they can earn their keep cleaning up the tank a little. While it is certainly true big catfish do best when fed only a few times per week, I'm not sure this is true for Corydoras which are simply so much more active.> The other nights I feed 2 1/2 shrimp pellets. These are little pellets, nothing like the Top Fin ones that are huge! They eat everything in under an hour so I feel they are not being over fed since they nibble a lot and play during feeding. Once or twice a week I throw in a couple of brine shrimp or blood worms(frozen). They seem very happy although I have one that hides a lot in the tree stump. This one is the biggest and I think she is a female, but that is not one with any white and I watch her more than the others for any sign of disease since she does hide. She just always has. When I had 3, 1 of the others would stay with her constantly, but now she stays alone mostly. <Corydoras frequently divide into subgroups, with one female to one or more male. The males will follow the female about. If they're happy, you'll often see some species of Corydoras spawn even in community tanks. Not sure Corydoras schwartzi spawns in aquaria though.> Not sure of these kind of dynamics but I can only guess it has to do with the make-up of the group. Here are my parameters:ammonia-0nitrite-0nitrate-Under 20chlorine/Chloramine 0GH-150KH-180pH-7.8 <All fine. Do keep the temperature on the low side though, ideally around 22 C and certainly no more than 25 C.> I do 20% WC's weekly along with vacuuming with battery powered Penn Plax vacuum. <Slightly more water changing would be recommended. 25-50% is my preference in freshwater tanks. Cheap, easy way to ensure good health.> I only use prime for my water conditioning, although I do add Bio Spira with new fish. <Redundant; a mature filter will adjust to reasonable increasing in stocking virtually at once all by itself.> It is a twenty gallon tall tank with a Penguin 150 filter. The only thing I can come up with besides that these are normal markings (then why don't they all have them) is that it could be a fungal or bacterial infection, or rubbing I have read about in wild collected specimen. <Fungal infections should look distinctly odd in texture, typically white and fluffy. While not uncommon on Corydoras, they are usually associated with serious physical damage and/or poor water quality.> Gee, that would mean my LFS lied to me. While I am sure not all that uncommon, it would really upset me as they have the best looking fish around and they are a small independent store that even carries Bio Spira. Thanks so much for you insight and this site, people like me who just don't have the experience to recognize these things appreciate all of your hard work very much. I spend a lot of time researching so I can only imagine how many years it took you to learn all you know. Thanks for sharing it with us. Debbie <Need a better photo to say anything sensible about the "white" patches. Cheers, Neale.>

Corydoras Concerns... hlth, acclimation... 2/18/08
Hi Crew, <Mike> Thanks in advance for your assistance with my question. WWM is a fantastic forum and reading the Q&As has become one of my regular daily activities. Keep up the great work! <We're trying!> I'm experiencing some problems with some Corydoras I acquired last Friday and am unsure how to proceed. The specs: 10 (U.S.) gallon quarantine tank. PH = 8.0 <Yikes! A bit high for most members of this genus...> NH3=0 NH2=.3 mg/l <Super yikes... very toxic. I'd at least be trading out prepared water, really discounting feeding... Reading on WWM re reduction...> NO3=0 Temperature=79F <Mmmm, what species of Corydoras are these? Some prefer cooler, warmer water...> Filtration = Whisper 10i in-tank filter Sequence of events: 1. 2/9: Tank set up. Water 50/50 from established main display tank and fresh - seeded with a pinch of fish food to start the cycling process <Good> 2. 2/14: Bio-Spira added. <Good> 3. 2/15: Received delivery from Drs. Foster & Smith containing 5 juvenile Carnegiella strigata and 5 juvenile (what were supposed to be) Corydoras trilineatus 4. Acclimated livestock by floating for 45 minutes and 2 hours of gradual addition of tank water to the shipping bags. <Mmm... I should make a few comments here... re measuring for incoming ammonia, pH to some extent... there are other preferred acclimation techniques for situations where animals have been boxed up for hours... vs. short trips from a LFS... Posted on WWM> 5. Upon release into tank noticed one of the Corys was struggling to maintain proper swimming orientation. Observed what I thought to be inflammation of the gills (gills appeared "bruised" reddish/blue) and clamped dorsal fin. Suspected a parasitic or bacterial infection of the gills. <Ahh! Very common... "burn" from the aforementioned accumulated ammonia, rapid change in surrounding water... the pH changing the "format" of the ammonia inside the fishes bodies, being much more toxic> 6. 2/16: Hatchets doing fine and taking food. All Corys foraging for food, but no improvement in the one showing distress. 7. 2/17: Morning: Hatchets doing fine and taking food. 1 Cory dead. 1 Cory showing distress (swimming erratically, struggling to maintain proper orientation, clamped dorsal fin). All surviving Corys displaying apparent gill "bruising" coloration. Researched on FishBase and believe specimens are Corydoras julii not trilineatus (based on spotted vs. reticulated head markings. A gill "bruise" appears to be normal coloration for julii, but not trilineatus). 8. 2/17: Afternoon: Hatchets continue to be doing well. Cory that was showing distress in the morning continued to degrade. Euthanized to end suffering. Surviving 3 Corys beginning to show distress, dorsal fin clamping. I've done a partial water change with water from my display tank (PH=7.3, NH3=0, NH2=0, NO3=0) <Good> reduced the tank temperature to 78 F (FishBase indicates julii likes a slightly cooler environment than trilineatus) and continue to monitor NH2. <Also good> Any idea what might be going on with these poor little guys and/or suggestions what I can do to help them? Thank you very much for you assistance. Mike <I do think they may have just suffered too much "shipping stress" and the mentioned gill burn... I would contact the fine folks at Dr.s F and S with your report, the likely incorrect species ID on their part, and ask for credit/replacement. Bob Fenner>

Cory Help... sel., hlth. 2/1/08 Hi! I have recently bought one albino Cory for my 20 gallon aquarium. Along side the Cory in the tank are 3 marble mollies, a balloon molly, 2 white fin tetras, and a zebra tetra. <No such thing as a "zebra tetra" -- do you mean a Zebra Danio? Small minnow with longitudinal gold and purple stripes.> My problem is my Cory is acting extremely weird. He swims up and down radically and never stays in one spot too long. Sometimes he just frantically swims around and around in the aquarium. I feed him using fish flakes and sinking pellets. But it seems as though he doesn't eat this food. I have had him for 4 days now. Could he be acting strange due to the presence of the other fish? Or is there something else that could be a contributing factor to this? <He's lonely, scared, and miserable -- and likely wondering why he was bought by someone who doesn't research their fish first, usually an omen of doom for unfortunate fish. Corydoras are *schooling* fish, and have to be kept in groups. Four is the minimum really, and you need six or more to see them at their best. So go to your retailer and buy some more. Albino Corydoras are usually Corydoras paleatus, so you can mix them with regular Corydoras paleatus (known as "peppered Corydoras" in the trade).> Sincerely, Michael <Cheers, Neale.> <<Well done Neale. RMF>>

Sick Cory, env. dis. 12/9/07 Hi crew! <Becky> I am having trouble with my peppered Cory catfish, Spike, and don't know what to do. I have had him over a year, and he has always seemed to have a reddish fin. <Ahh, a sign of something incompatible with this fish and its environment... chemical, physical, social...> But recently, it has gotten bigger and the skin is falling off. I have had this happen in this area before, and have treated it with just Melafix and it has gone away, but always seems to come back. His fin has become obsolete, he can't use it. Other areas of skin on his body seem to be falling off as well. I haven't heard of or seen anything like this. <The clue that the Melafix product had an improving effect leads me to speculate that the water quality is incompatible here. Corydoras live in soft, acidic waters by and large. What is your water like?> I have tried AquariSol and adding a little extra aquarium salt to my tank, <And Callichthyids do NOT like salts in their water...> but they don't work. My other fish in the 10 gal. tank all seem to be ok, except for Spike. <What are the other fish species? This is a very useful clue... as the others likely have dissimilar water quality tolerances> I isolated him in a smaller tank (1 gal) but he acted very weird, so I moved him back into the tank. Any clue what it could be/ what treatments I should use? Thanks, Becky <Please read here: http://wetwebmedia.com/FWSubWebIndex/callcatdisfaq2.htm and the linked files above. Your answers are there. Bob Fenner>
Re: Sick Cory, env. dis.. NealeM addenda to Callichthyid dis., env. 12/9/07
Hi Robert, <Neale> More a bit of information than a correction really. Where you said today that "..Callichthyids do NOT like salts in their water..." that's only true up to a point. <Oh?> It is certainly the case that Corydoras do not come from brackish water. But there are true brackish water Callichthyidae. Hoplosternum littorale actually seems to prefer brackish water, growing more slowly in freshwater than brackish. It tolerates up to 16 ppt.* Unlike Callichthyidae generally, it is absent from soft/acid waters. I only learned about this a year or so ago, so it never made it into the brackish book. Shame, because it strikes me that this hardy and very robust catfish would be a superb addition to tanks with mollies and such. <Mmm, thank you for this> Apparently also thrives perfectly well in polluted, hydrogen sulphide > rich waters where other fish show signs of ill-health. I thought I'd share though. No need to publish this or anything. I happen to revel in these exceptional members of either freshwater or marine families that "break the rules" and do precisely what you'd not expect. I felt you'd be amused, too. Cheers, Neale * See 'Biology' section here for references: http://nis.gsmfc.org/ > nis_factsheet2.php?toc_id=188 <Thanks again. Will accumulate/post. BobF>

Re: gray spots on Orange Neon Cory 12/7/07 Hi, I have yet again another problem with my Corys. <Oh?> Last week my 30 gallon female Betta/ Cory tank experienced a bout of something that was best described as Epistylis. I was in contact with Neale and with his great advice and help I think we cleared that problem up. All is well in that tank. <Good-oh.> Neale suggested as a general rule for all my tanks to do 50% WC per week, which I have started doing. I was only doing 25%. I treated the Betta/Cory tank with Jungle's Tank Buddies for Fungus and then after two treatments of the Fungus meds, added Pima Fix for the Cory with healing fins and barbels and I have noticed regrowth on both areas. Should I do more Pima Fix and for how long? Something else? <I'd keep using it until the fish are 100% healed. Pimafix is pretty mild stuff and unlikely to cause any problems.> I am also running a 55 gallon community tank with two dwarf Gouramis, two gold gouramis, 1 blue three spot and 1 Opaline Gourami, 5 Schwartzi Corys, 6 Orange Laser Corys, 7 scissor tail Rasboras, 1 pair black mollies, and a pair of orange platies. <Ok.> The tank has lots of live plants, Fluorite bottom about 3/4 deep, an HOB filter and a sponge filer rated for 40 gallons. After I removed the carbon, as suggested, I placed 3/4 cup of Zeolite in the HOB filter for ammonia and left the coarse sponge like screens in for filtration, OK? <Zeolite is almost as useless as carbon. Zeolite removers ammonia. Nothing else. That's all it does. If you have a biological filter that is working properly, the Zeolite isn't adding anything useful to your filtration system. It's just as waste of space and money. Zeolite is primarily for tanks where biological filters can't be used, e.g., soft water tanks at pH <6, or hospital tanks set up at a moment's notice.> Water parameters are temp. 80-82 degrees, Ammonia 0, nitrate 0 and nitrates 0. PH is about 7.2 before and around 7.5 right after WC. <Ooh, a little on the warm side. Aim for 25C/77F. Corydoras especially don't like overly warm water.> Here's the problem. Two of the Orange Laser Corys have what look like gray patches on their heads. The patches are not perfectly round, one has a crescent shape patch and the other's is sort of oval. Both have a lighter, as in color and thickness, patch near one gill. These appeared after the 1st 50% WC, which I am careful about as regards to matching water temps. <Water changes shouldn't cause any problems if done properly. Water temperature isn't really a factor, because Corydoras LOVE cool water splashed into their tropical tanks. It's how you get them to spawn. But you do need to check you're using a suitable dechlorinator, for example one that removes Chloramine if you live somewhere that Chloramine is used.> The patches are not like fibers, about 1/4" in diameter, though irregular. They are not moving, I'm sure not Velvet, certainly not Ich. Do I have a fungus or a bacterial infection going on? <Sounds like it. Treat with combination Finrot/Fungus since we don't know if it's a bacteria or fungus at work here.> I treated the tank with Jungle's Tank Buddies for Fungus as I did the other tank since the color of the spots appeared, initially, the same as with the other Corys in the 30 gallon tank, but the results were totally different. The Orange Corys appeared to be responding to treatment, but then the gray soft ( as in non reflective or velvety) appearance of the spots seems to dissolve, for lack of a better way to explain it, and then the spots or patches seem to be concave as if there was just a wound left underneath. BTW, I treated twice, as per directions which were four day treatments with 25% WC between applications. The spots were concave after the first treatment, but no improvement and no change in the lighter affected spots near the gills. <Hmm...> I am at a total loss as to what to do now at the end of the second treatment. I have looked everywhere for an accurate picture of the condition on the web and nothing seems to match exactly. It could be sap, it could be Columnaris, it could be?????? But, now it doesn't sound like Epistylis! <Could be Columnaris (a.k.a. "mouth fungus") but could be something else, too. Use a combination Finrot/fungus medication and chances are good it'll clear up, even if you don't know what the precise problem is.> I should mention that the tank also had something else going on in it and the Jungle Buddies fungus cure worked in conjunction with medicated food. The largest Blue 3 spot Gourami had two red spots, one near the anal fin and one on the head. Hence the medicated food and they have now healed. Bacterial infection due to poor water quality? <Most probably.> One of the Dwarf Gouramis had what looked like it might be the start of a spot near it's mouth and that has also disappeared. More like an abrasion, but never got red or raw, just scales that didn't look "right". <Quite possibly damage from fighting.> None of the Schwartzi or other Orange Laser Corys have shown any signs of the spots and all but one Orange Cory is still very active and eating. No signs of fin or barbel damage in any of them, including the two affected. <Good. Treat and wait.> I have been to three LFS and bought whatever I can lay my hands on, Help! I think I've read so much on the web and your site that I'm now paralyzed with indecision as to my next move! <Combination Finrot/Fungus medication is the way to go.> Thanks for any advice and especially this site. It is so informative and the first place I go to now when I have any questions regarding fish, aquariums, plants, you name it. It is the best out there. Polly <Glad we can help. Good luck, Neale.>

Re: gray spots on Orange Neon Cory 12/07/2007 Hi Neale, <Hello Polly,> Sorry I didn't write back immediately. I did another 50% WC, instead of the recommended 25% on the Jungle Fungus Tank Buddies and dosed the entire 50 Gal tank again. This will be the third round of meds. <Sheesh... that's a lot of medication. I'd be switching brands, if that's an option for you. I've learned the hard way that sometimes one medication works where another fails. Mostly this is with Whitespot/Ick, but perhaps worth considering here.> The spots on the two orange Corys are now whiter and a bit ragged looking. One Cory is lethargic and the other is still active an eating. None of the other Schwartzi or orange Corys are affected with any signs of this condition. <White stuff is usually dead tissue, whereas grey stuff is mucous. So given this is white stuff, I'm guessing we have necrosis going on, meaning that things are pretty bad. If this was me, I'd be thinking about saltwater dips as a supplement. These are basically baths made with aquarium water and 35 grammes of salt (any kind, really) per litre. You dip the fish for a period of time, once per day. The idea is the salty water cleans the wound and destroys the fungi/bacteria causing the problem. It can work very well, but Corydoras are not especially salt-tolerant, so you'd have to do this carefully. Perhaps dipping at first for 1 minute, and seeing how things go. If the fish is fine, try two minutes the next day. Salt-tolerant fish can stand up to 20 minutes, and this does a great job, but in this case, I'd be limiting myself to no more than 3-5 minute dips.> I didn't mean that the spots appeared after the WC and the WC was the condition was probably already working it's black magic on those two Corys and the WC was most likely a lifesaver for the others in the tank, who certainly would have become infected too had it not been for the WC. Sorry. <Agreed. Water changes normally only do good.> How many times should I stick with this med if it doesn't appear to be working? And, what antibacterial med should I use with it? Should it be after this treatment or in addition to the treatment? ( the Jungle Fungus med does state that it treats both, but I don't see any signs of improvement on the Corys. ) <Stop using one medication when you start with another, unless it *expressly* says you can use in combination with some other named medication. My gut feeling is you're going to need a Maracyn-type systemic antibiotic to fix things here. Such drugs are available over-the-counter in the US, or you can get them through a vet. Maracyn is Erythromycin, each Maracyn tablet is apparently 200 mg Erythromycin and meant to be used one tablet per 10 gallons of water. So if you can't get Maracyn itself, an appropriate concentration of Erythromycin should work just as well. I'm not a vet though! So take this suggestion for what it is, my best guess!> I just spent an hour looking at each of the fish in the 50 gal tank and noticed that one of the yellow Gouramis is not tolerating the treatment too well. She/he is hanging out at the top of the tank in the corner and not interested in food. It was active and hungry this morning. The red/blue dwarf Gourami is not looking too active either. His abrasion, or whatever it was, is healed, but now he looks like he's growing a little double chin below his mouth! Nothing is red or raw, but it is worrisome to me. <I'd stop feeding, and also do something to increase oxygen concentration. Slightly lowering the temperature will help (to 74F/23C) as will adjusting any filters or air pumps to maximise circulation of the water. Lowering the water level slightly so that the spout of water from the filter makes more splashing can help, too, by driving off CO2 and improving oxygen absorption.> The reason I had the Zeolite in the filter was that I had to remove the carbon and thought it might control any ammonia during the first two treatments. Now I realize that with the sponge filter and the plants and other items in the tank, they will take care of the ammonia problem. Is that right? Sorry to be so dense. <Yep. Healthy filter bacteria do a better job than Zeolite anyway. But if you've had a lot of Zeolite in the filter, potentially the filter bacteria will be under-developed, so do check for signs of ammonia. That'll correct itself within a few days though, because you should have at least a semi-healthy population of filter bacteria. So it's not like cycling the tank from scratch.> You asked if I was conditioning the water. Yes, I use AquaSafe, but recently read that it might acidify the water more than other products. Is that true? <No idea, and can't imagine it'd be that big of a deal.> Is there something that is better for hard well water for conditioning in your opinion? <No. It's mostly about Chloramine, which some water suppliers add to the water. A few dechlorinators don't treat it properly, and you end up with extra ammonia. I'm not aware of any specific problems with well water.> I also age the water for at least a day and have four 5 gal buckets, and 5 or 6 gallon containers set aside. <Probably redundant, but certainly not doing any harm.> I keep reading different people's methods for their WCs and wondered if it's OK to heat a bit of tap water, condition it and add it to the aged/conditioned water to heat it up? <There's nothing wrong with mixing hot/cold water right from the tap. Dechlorinators usually treat copper from the pipes. The only bad water is water from a domestic water softener. Fish don't like this stuff at all.> I had to do that this morning to do the 50% fast WC before I caught the 10 AM boat to make a doctor's appointment. Now I'm wondering if it has anything to do with the two gouramis not doing so well tonight? <Unlikely, and in any case should settle down. I once added almost ice-cold water to a tank filled with parent and baby cichlids. I was in a rush, and not thinking. The fish went crazy, rolling onto their sides as if stunned. An hour later they were fine. Fish are actually quite robust animals, and when we see problems, it's usually because the problem has beaten their immune system and blown into something serious. Provided you keep the fish healthy in the first place, they almost never get ill. Honest!> Also, really stupid question now, how is it people use Python systems straight from the tap and add the conditioner at the same time and get that right? <The basic idea is you add the dechlorinator to the tank first, and then add the water so it instantly mixes with the dechlorinator in the aquarium water. I'm old school. I use a plain vanilla hose pipe and suck the water out to start the siphon.> Is that a good practice, or are they doing it out of necessity with large tanks or multiple tanks? <Lots of people like them. I'm not one of them though. I tend to mix rainwater with tap water, or salty water with tap water, to create specific water conditions. So Pythons aren't terribly useful for me.> right now to age is impossible and I was just wondering if I could do it too without adding more problems. <Should work fine. Ageing water isn't terribly important these days, especially if you use a decent dechlorinator and have lots of circulation in the tank to mix the old and new water properly. Anything that makes water changes easier is a good thing, because you'll do more of them in less time and with less frustration.> Thanks again, and I'll keep you apprised of what happens next. PS. Angelfish still looking good, just did their weekly 50% WC tonight, bought them their own 28 gallon tank and will move them out of the 12 next week. <Very good.> Polly <Cheers, Neale.>

Re: gray spots on Orange Neon Cory 12/9/07 Neale, <Polly,> OMG, we're into metrics...I don't do metrics well, too old for the change over! lol Nearest I can figure out, with a dilution of that percentage for Corys and rounding off, would be 35 grams to 1 litre = 2 tablespoons per 1/3 US gallon H2O, would that be best? Is that right even? <Ah, metrics are actually easier for this kind of thing, because normal salinity, 35 parts-per-thousand, is identical to the concentration in weight measurements, 35 grammes per litre. As it happens, I have a little computer program designed for calculating salinities and switching between metric and US units, called "Brack Calc", which you can download and play with at the link below. By my reckoning, normal seawater salinity is about 4.7 ounces of salt per US gallon. http://homepage.mac.com/nmonks/aquaria/aqua_soft.html You'll have to experiment yourself and see how that works out in teaspoons.> Both Corys doing badly now and I fear the worst. Should I do a 50% WC on the 55 gal tank to remove the Jungle Fungus Buddies med and do the E-mycin treatment instead, or let this treatment run the remaining three days of it's course? <Change water and switch medication. Nothing to lose, everything to gain.> Isolate them and do the E-mycin in the QT tank? <Leave them be. The stress of moving them won't help.> Or, continue treating the 55 gal since there might still be something contagious there? <I'd treat the quarantine and the display tank.> I know what you said last time, and that was the entire tank at this point, so am leaning in that direction, but want to hear you say that's right. <I almost always treat tanks rather than specific fish, except for things like saltwater dips, and even then the dip is to assist the medication, not replace it.> I'm going to change the positioning of the HOB filter and sponge filter to change the direction of the water flow a bit and then add an air stone near the bottom of the tank to increase the oxygen and movement. I used to have one there before this all started to turn sour and took it out as it ticked off the dwarf red Gourami, "Il Duce", who has been using all his spare time building floating plant islands and building bubble nests, also a great pain in the butt when it came to constantly clearing the slots in the bottom of the filter uptake, but he would have his way. <Hah! We see who wears the trousers in your household...!> I tried to control this plant yanking obsession of his by taking a piece of tubing and turning it into a floating circle for him, plopping his plant material in it and floating it in one corner away from the filter, but he plays with it too much and the other gouramis like stealing his plants for their own islands. We now have three floating islands for the gouramis! Does keep the floating stuff in check, but the air stone pushes them around and they are not happy. Tough love is called for I think. lol <In the old days people use to break Styrofoam cups into segments, and Gouramis seemed to love building nests under them. They (the cup fragments) float really nicely, curve upwards, gathering plant bits underneath them. Worth a shot.> The blasted heater is hard to adjust and I am going to swap it out for a different heater and see if it can more closely control the temperature level. Why is it that you can find a heater that works perfectly, from one company, buy another of the same brand and get totally different results??? UGH! <Heaters are often annoying. I find that some designs -- those with rubber caps over the entire adjuster-end of the device -- often become stiff with age. The effect of water and/or hardness I suppose. I prefer the ones where the adjuster knob is free from the rest of the cap. In any case, one old trick is to use two under-powered heaters for a tank. That way, if one gets stuck, it isn't powerful enough to boil the fish. Conversely, if one fails completely, the other heater will keep the tank from getting dangerously cold. So if your tank needs 150 W heater, get two 75 W heaters instead.> I had lowered the water level a bit after that fast WC yesterday and figured I would leave it that way for awhile to increase some splashing, and really a good rationalization since I didn't have the time to add the remaining two or three gallons before the boat time. <Cool.> Thanks for the info on the Python and WC ideas. Indeed, not worrying about ageing the water makes life easier and better with more WCs for the fish. <Agreed. Fishkeeping should be a low-impact hobby. If you're spending more than 45-60 minutes a week on maintenance, you're doing something wrong. The whole point of the thing is to relax, watching the colourful beasts swimming about merrily (or violently, if you're keeping cichlids).> Thanks, Polly <Good luck, Neale.>

Re: gray spots on Orange Neon Cory 12/10/07 Neale, <Polly,> lost the two orange Corys in the night. <Ah, too bad.> I hadn't changed out any water or the meds as of last night and when I got up this morning and checked the big tank, found the two dead Corys and the other orange Corys were acting distressed. One was "running" up and down the side of the tank and hid if I came within sight! The others didn't flash or swim up and down, they just hid on me too. I reckoned that the meds might be stressing them. Took out 10 gallons of H2O and then added that and the water I hadn't put back in two days ago. Makes about 12-13 gallons in to dilute some of the meds. Is it possible that it took two days for the meds to distress this much? <Possible. Unlikely, but possible. Most medications are more or less toxic to fish, and we use them on the basis that *most* of the time they kill the infection before they seriously harm the fish. But some fish are peculiarly sensitive to certain medications. I've not personally experienced this with Corydoras, but it may happen with some species and some medications I've not kept/used.> I see a bit of brightness, as in orange or reddish, near the gills of one of the orange Corys, which is hard to detect with their coloring, but the others aren't showing any signs of red at all, just hiding on me in their little cave. <I REALLY need a photo to understand what's going on here. We've pretty much run through the list of common infections & their treatments.> The other fish seem to be normal, just a bit curious as to all the new water coming in and old going out, but otherwise OK. The 5 Schwartzi Corys are still oblivious to anything different happening, are acting normal and eating, nothing unusual on their bodies or in coloration. No fin or barbel loss, redness, nothing that I can see with the naked eye or the magnifying lens and flashlight. This is true of the orange Corys too. No fin or barbel loss either, no spots or patches of fungus like things. <Good.> The only thing I can imagine is that it was too much medicine going in and I should have done either a lighter dose or perhaps pulled the two affected out of the tank and waited to see what would happen???? I tried to dose with the amount of water actually in the tank rather than the tank's potential capacity. <Sometimes it is worth doing half-doses of medication. If the infection is slight, half-doses might help with reduced risk of problems. But if the infection is serious, you usually need the full dose to get the desired results.> I have to believe something else is going on in this tank and there is something I can't see, or one is a carrier of something in there with the rest. What else can it be? Could they have some little parasite that is in the gills that is undetectable? <I really don't know. Without seeing a photo of the fish in question, it's very difficult to be sure what's going on.> OR, is this a progression of a disease which is just taking out the weaker fish in sequence? <Certainly possible. This is precisely how Neon Tetra Disease works through an aquarium, knocking off a fish at a time, usually once every few weeks.> I'm totally baffled by this. The orange Corys came through the Ich outbreak without any of them catching a spot, have been looking really good until this hit all at once. Probably not all at once, you're saying, but brewing away in the depths of the tank and had I done the 50% WCs all along this wouldn't have happened. <Ick is usually a very obvious disease, and if it becomes fatal, it is obviously serious with white spots all over the fins and flanks. So we can probably discount this. Ick can make fish sensitive to secondary infections, and it is possible that this has happened here. Since "secondary infections" covers a lot of ground, it's difficult to identify the pathogen without access to a microbiology lab. Pseudomonas and Aeromonas are the two commonest bacteria, but there are many others.> Should I still try the E-mycin or just do more WC tomorrow? <I'd try the Erythromycin at this stage. Do two big water changes before though, to flush out as much old medication as possible. Maybe 50% tonight, then 50% tomorrow morning, and then dose the tank. Do take care to siphon up any detritus in the tank while you're at it. The 'cleaner' the tank, the better the antibiotic will work.> I'm starting to wonder if the Dwarf Gouramis had something up with them when we introduced them to the tank about three weeks ago. <Dwarf Gouramis are fish I would never, ever keep. They are notorious carriers of viral and bacterial infections, to which they usually succumb very quickly. Whether said infections can jump to catfish I do not know. Anything's possible I suppose, but I haven't heard this particular thing happening before.> They were Qt'ed for two and a half weeks, showed no signs of anything, but were stressing each other out so much that we finally added them to the big tank. They have been doing OK, but might have carried something in as yet undetected. <Indeed. Hard to say.> Thanks for the quick reply, once again, Polly <Cheers, Neale.>

Re: gray spots on Orange Neon Cory 12/11/07 Neale, <Polly,> I have tried all day to get a picture of the Corys, but they aren't cooperating one bit. When they do come out they are in constant motion and once the flash on the digital goes off, they go into deep hiding. <Oh.> Interesting thing is that they look and act normally, when they come out of their cave and rock hidey holes. This is only when they don't see us and they were frantic to eat when I fed the tank! Could I have cleaned the tank bottom too well? LOL Doubt it, but its not nearly as bad, which didn't appear that bad, to begin with. ( also, we've kept their end of the tank without lights for most of the day to make them more comfortable about coming out.) <No, don't worry, clean is good!> I shined the flashlight on all the oranges, when I could sneak up on them, and they all look the same color in the gill area. Think it's a trick of the light with their Neon orange coloring. Depending on how they turn, the gills look reddish or gold. Now I think I must have panicked and they don't have a gill problem. They all look exactly the same in the gills. <Good.> My mother, whose chair is right next to the tank, has been watching them closely all day and she thinks they are more out and about than yesterday, none have "run" up and down the tank side, flashed or done anything unusual except the hiding. She admitted to dropping a little food into the tank to see if they'd come out and sure enough, they rushed out from under their cave, ate and then swam right back in when they were done. The Schwartzi are not acting this way at all and they all ate together, including our large blue 3 spot Gourami who loves the algae pellet too. That didn't upset them either. <Very good. I'm glad your Mom is getting involved. The more people who recognise healthy fish/behaviour, the better. It's like having more spies! You get a heads-up on problems when someone else in the family says, "Gee, that Catfish is looking a bit odd this morning".> The Schwartzi and the oranges used to like to hang out at the end of the tank with the sponge filter and I've changed the sponge filter to the other end of the tank. It seems unlikely that that could be the problem. I haven't read that they are territorial. The Schwartzi are now more at the sponge filter end of the tank. The oranges in The Cave. <Corydoras aren't remotely territorial. They live in schools of hundreds of fish in the wild, often mixed species groups but not always. Some species won't school together, and simply ignore each other.> Still no marks or spots or growths on them and no deterioration on barbel, fins or tails. Just this weird behavior. Could they be so stressed from the loss of the two other Corys? <Stressed is perhaps not the word, but Corydoras do become more nervous/less day-active when kept in too-small a group.> There were 6 and now are four, but there are still the 5 Schwartzi Corys who they eat with during their feeding frenzy. <Ah, I'd aim for at least 6 of each, ideally more.> This brings up the question of whether they are getting a proper diet. I give them half of an algae pellet every day and every other day a few shrimp pellets. They scavenge for any leftover food from the top feeders and I have cut back some on that food as I thought we might have fed them too much. They are fed twice a day and sparingly. Could their diet be deficient? <No. It's almost impossible to starve fish because they have very, very low food requirements. Most of what we eat is effectively "wasted" on thermoregulation (I think it's 80% of the calories, but I'd have to check). Most fish do not control their body temperature this way, instead relying on the warmth of the water to keep them at the right temperature. All they need per day is enough food for movement and growth. Literally a single flake will supply this for a small, inch-long tropical fish. Anything else is a bonus. Corydoras also eat a lot of plant material in the wild, and will graze on algae and decaying plant matter.> I'm totally baffled by this turn of events, think I will not add any other meds to the tank right now and wait another day to see what happens. Is this wise or should I really do E-mycin to the entire tank without any other indications? <If we think the gills are normal, and the fish show no other symptoms, it may well be time to leave things be.> If this is just some stress related behavior I really don't want to add to it. I'm going to do another big WC tomorrow and hope that they aren't even more reclusive, but it will make the water conditions even better and I'm hopeful that it will make them more comfortable. <Water changes are good!> Will try and get some pictures, but don't know if they'll be more cooperative or not. Thanks again, Polly <Good luck, Neale.>

Possible sick Cory cat- frayed fins 11/14/07 Hello, <Hello,> I have tried searching on the form and internet but a little stumped as to what it could be or whether the symptoms are early signs or even symptoms at all. Five days ago I got 2 small (0.5 inch) panda Corys into my new tank. <Glad you're buying your fish a few at a time for your new tank, but Corydoras should always be kept in groups. Ideally at least 5 specimens. They are shy, schooling animals and in too-small a group will never be happy. So plan on getting three more later on; trust me, once you see your *school* of catfish scooting about the tank and happily playing in the water current, you'll understand why this is critical.> The tank was setup about 3 weeks ago seeded with aquarium gravel from an established tank and fed with fish food over several days to get the cycle going. <A good plan, though gravel doesn't have as big an effect as taking media from the filter, my own preferred way to "jump start" a new tank.> Did a 30% water change before putting the pandas in. I originally bought 3 but 1 one them died the next day, it had internal hemorrhaging in its belly when I found it dead. <Ah, not good. Internal bleeding rarely happens for no reason. I suspect that rather than internal bleeding (which would be invisible to the naked eye unless you dissected the fish) what you are seeing is a secondary bacterial infection that caused the skin on the belly to become inflamed. In which case, water quality was almost certainly the issue.> The other 2 Corys looked ok until this weekend, 1 of them started showing a frayed top fin with white edges. He seems paler all over as well. The back fin has 2 white streaks on it with 2 small red spots on the edges of the fin (sorry no pic). <Sounds a lot like Finrot. The white streaks are dead skin, and the red spots are sites of inflammation.> He is active and eating a little but not as active and eating as when I first got him. Water is: ammonia 0 nitrite 0 nitrate 10 ph 7.6 Temp 78 F <A bit too warm. These catfish come from waters close to the Andes and generally experienced fairly cool conditions. Between 20 and 25 C has to be considered the ideal. Anything above that places heat stress on them, which in the long term does them no good and shortens their lifespan. When selecting tankmates, be sure and choose other species, such as Danios, that inhabit similar conditions rather than, say, Cardinal tetras, which need warmer water.> I know the ph is high for them but I read that they can adapt. <The pH is largely irrelevant, providing it is stable. Corydoras are fine across pH 6.0 to 8.0. What they don't like is variations in pH.> They were at the LFS for one week in their tank water so I figure they would be ok. The water is super hard here as well. <Shouldn't cause any problems either. While Corydoras panda naturally inhabits slightly soft and acidic water in the wild, like most Corydoras it will adapt fine to hard, alkaline water.> The white lines are not defined spots, so I ruled out Ich, and the white frayed fin does not look cottony, so not sure if its fungus or what. The edges are all rough though, like the fin is blunted, its not sharply defined anymore and it has gotten worse since the weekend. <Finrot. Almost certainly caused by poor water quality, either at the retailer or in your tank. In either case, treat with commercial Finrot remedy at once.> My other panda seems fine with clearly defined fins and color. I have a feeling though the affected panda is sick since not as active. what is going on since my water parameters seem ok and will it get worse? <Corydoras panda is thank you very much for your help sincerely, Terri <Hope this helps, Neale>

Re: possible sick Cory cat- frayed fins -11/14/07 Hi Neale <Hello Terri-Ann.> Thanks so much for your wisdom. Now I feel horrible because I spent so much time doing research and I thought it would be ok to get panda Corys! Well m a little confused about what you said in regards to my Temp at 78 F: >>>A bit too warm. These catfish come from waters close to the Andes and generally experienced fairly cool conditions. Between 20 and 25 C has to be considered the ideal. Anything above that places heat stress on them, which in the long term does them no good and shortens their lifespan. << As 78 F is 25.5 C is this not ok for them? Its only 0.5 degrees outside their ideal range? <You might be fine, especially if you make sure there is good water circulation in the tank and add aeration in summer if the water gets substantially hotter than this. One of the big problems with Corydoras that isn't understood is many, many species are either subtropical or low-end tropical fish. Relatively few (if any) come from the piping-hot water conditions favoured by Discus, Rams, Gouramis, etc. On the plus side, Corydoras are air-breathers, and can adapt to what is (to them) overheated water conditions. Still, it's one more factor that can stress them if conditions aren't perfect to start with.> I feel terrible because I'm thinking I should have gotten a different Cory, one from warmer waters. The reason I would like to keep them at this T is because I plan on adding 1 Betta and 4-5 Rasbora or tetra species. My big planted tank at home (29 gallon) hasn't been setup yet but was planning to put warmer south American species (Apistos, Neons, bronze Corys and Otos) in there as well, so my pandas cant be moved there either. what should I do? <Funnily enough, neither Neons nor Bronze Corydoras like warm water: both come from low-end tropical conditions. Neons come from waters at 20-25C (68-78F), while Cardinals want water in the 24-28C (75-82F) temperature range. So while we often think of them as interchangeable species, they actually come from completely different thermal regimes. Keeping Neons too warm is one reason many people have trouble keeping them alive (and conversely, keeping Cardinals too cold makes them sensitive to disease). Bronze Corydoras come from the subtropical parts of South America. While fine at 25C (78F) they aren't a viable choice for the 28-30C (82-86F) range favoured by some Apistogramma as well as Rams, Discus, etc. Temperature is a much bigger problem than many aquarists realise, and before putting fish together you do need to establish whether their thermal tolerances overlap.> >>>;Glad you're buying your fish a few at a time for your new tank, but Corydoras should always be kept in groups. Ideally at least 5 specimens. They are shy, schooling animals and in too-small a group will never be happy. So plan on getting three more later on; trust me, once you see your *school* of catfish scooting about the tank and happily playing in the water current, you'll understand why this is critical.><<<< I know that they should be kept in groups, so thought 3 as a minimum would be ok (will be getting them another panda friend in a month). Is this ok? I believe I have a very overstocked 10 gallon tank even with a future planned 3 Corys 1 Betta 5 Rasbora <Well, I'd skip the Betta to be honest. If nothing else, it might get nipped by the Rasboras. But if you want a Betta, then go for it. All these should be fine at 25C (78F). Bettas are more sensitive to cold air than cold water. So make sure you have warm, humid air over the tank (i.e., use a lid or hood of some sort). Three Corydoras is certainly possible, but they'll never be as much fun as in groups. I'm watching my school of seven Peppered Corydoras (four parents and three of their offspring from last year). Watching them chase each other, rub whiskers, and, for the last few days, lay eggs all over the tank is part of the fun of keeping them. And trust me, until you've bred Corydoras, you haven't kept fish! Their "kittens" are sickeningly cute.> what do you think? I don't think I can put more Corys in there! <Agreed. Go for 3 now, and when you get a 20 gallon tank, add three more.> Now about the Finrot issue: Yesterday I did a 40% water change treated with dechlorinator. The affected fish also seems a little bloated. What is going on??? How can this be an issue of water quality since I checked all my parameters before I put fish in and even now the water parameters seem ok???? <Not sure. Do check the ammonia or nitrite level 30-60 minutes after feeding. Sometimes these go up after meals: the problem isn't that the filter doesn't work, but that it is overwhelmed. In any case, provide water quality and chemistry are good, and you do water changes on a regular basis, then treat the Finrot and see how things go.> 1) I just bought both Jungle Fungus Eliminator and Mardel Trisulfa, which one do I use? The Jungle med has sodium chloride in it, is this safe for Corys? <Corydoras aren't wild about salt. They'll put up with it at low doses, but they don't need it. These medications certainly are appropriate (though I have no personal experience of them).> 2) do I isolate him into QT tank? Will this stress him more than if I leave him in the 10 gal and treat the whole thing? I'm worried that the 10 gallon is new and don't want to mess with the bacteria, also I don't want to move the Cory again, he was just transported from the LFS 5 days ago and they need to be with other fish. <Leave him be. Treat the tank. Be sure and remove carbon from the filter. Lots of people make this mistake, but carbon REMOVES MEDICATION!> 3) Do I even medicate at all? Or just do 30% daily water changes? I'm just worried since I read at how rapid fin rot can attack the whole fish. <Treat for Finrot, do water changes when course of medication finished (usually you have to leave the medicine a few days to work).> Hopefully you can get back to me ASAP as I will wait for your advice before I treat... thank you very much for your time, take care.. cheers Terri <Hope this helps, Neale>
Re: possible sick Cory cat- frayed fins -11/14/07
Hi Neale thanks for your quick response! I did as you suggested and treated the tank right away with Jungles Fungus eliminator. Now I have checked both the Jungle website, the internet and the instructions and cant find a clear answer. Will this type of med kill my good bacteria in my filter? If not is it just antibiotics that kill the good bacteria? What other meds for sure kills good bacteria? <No, these won't harm the filter bacteria. Assuming you use aquarium medications in the way you are instructed, they're completely safe.> Can I feed my Corys will they are medicated? <Yes, but you might want to make 100% sure you aren't overfeeding, and certainly don't give them more than one meal per day.> The tank looks like a yellow stained mess, so I'm not sure about feeding regime and adding food when they are being treated. <The colour from the medications tend to dissipate quickly. They don't do any long term harm, and the fish don't care.> Also on the side, I am feeding the 2 little guys half a shrimp pellet every 1-2 days, but it takes them forever to eat it. Usually by overnight its gone. Should I be letting the food pellet sit for only 10 minutes and then take it away from the Corys? <The golden rule is feed nothing that isn't gone after 10 minutes. I'd stick with that. Use softer foods or foods in mouthfuls they can swallow easily. Wet flake works fine with Corydoras, and there are plenty of catfish-specific foods. I'm not wild about dried shrimps and other dried animals as staple food items. They don't have terribly high levels of nutrition, and seem to cause constipation in fish given them too often. Use as a treat, maybe once a week.> They seem to like to come back to it and nibble on it all day long. <Indeed. If you must give them "nibbly" food, opt for something vegetable based, as this is unlikely to cause water quality problems (less protein). Sushi Nori or sliced cucumber would be ideal. Corydoras eat a lot of plant material and algae in the wild, something we overlook in aquaria at out peril.> Thanks so much Neale, you're awesome! <Aw, shucks!> cheers Terri <Cheers, Neale.>

Albino Cory and fin rot -- 10/18/07 Hi Bob-- <Well, it's Neale right now; hope that'll do.> I hope you are doing great. As always, let me please start with thanking you for the WWM web site and opportunity to share my concerns / problems / questions with other aquarists. <Cheers!> I do have a question about and a problem with fin rot in Albino Cory. <Ah, Finrot... almost always an issue with water quality. If it ever gets caused by other stuff, that's news to me. So, always review water quality while treating Finrot.> Few months ago my little Albino got that disease. In the aftermath of that fin rot my Albino lost its dorsal and pectoral fins... ;--( I acknowledge I was afraid to medicate the fish assuming that changing water will be much more beneficial than dropping medication... Perhaps, I was wrong. <Indeed you were wrong. It's a 2-step process. Water changes are essential to maintaining good water quality. No question. 50% weekly is my recommendation. BUT, while using a medication, you can't do water changes. Water changes would (obviously) dilute the medication, reducing its efficacy. This is also why you remove carbon from the filter (if you're using it, and you shouldn't be in my opinion). Carbon removes medication, reducing its efficacy as well. Regardless, it's not an "either/or" situation -- you do water changes to prevent problems, and use medications (stopping water changes) when problems arise. When the medication course is finished, resume water changes.> On a regular basis, every Wednesday and Saturday, I change 30% of my 25-gallon tank water... The pH range reads between 6.8 and 7.0. The water temperature is ca. 76 F. The ammonia level is 0. <All sounds reasonable. I personally find Nitrite more informative than Ammonia though; ammonia can come from inorganic sources (e.g., tap water) and its absence tells you nothing about the Nitrifying bacteria that turn Nitrite into Nitrate.> I keep lots of plants (Cabomba & banana) and make sure the water circulation is quite fast (I have one Emperor filter + one small Hagen filter for 10-gallon tank and 2 oxygen stones). <10 gallons a little on the small side for Corydoras paleatus (which is likely what you have).> I am not sure what I am doing wrong, but there must be something I do not get right... I noticed that my Albino started loosing its caudal fins (I observed the fin became quite ragged and 1/2 "eaten"). <How often do you clean the substrate? It's often said that dirty substrates can promote secondary infections on benthic fish. No idea if this is true or not, but stirring the gravel every few weeks before doing a water change can't do any harm, so long as you don't uproot the plants.> At this point I have to acknowledge that I am clueless ;--( and desperately looking for help, before the entire caudal disappears. <I see.> Do you think that I should place Albino in a hospital tank and treat it for the fin rot? <No, Corys like to be in groups, and keeping them alone will stress the fish in question. Besides, you may as well treat the tank.> If so, what is the best medication (least harmful) I could offer to that little fish. <Corys are fairly tolerant of medications compared with more sensitive catfish. So any combination Finrot/Fungus medication will work here. Ideally, get something safe with sensitive fish and/or invertebrates, but it really doesn't matter too much. I happen to find eSHa 2000 very good with sensitive fish, but as far as I know it's only sold here in Europe. Mardel Maracyn is one alternative you might consider.> Sorry to "bother" you with my question... I hope you will be able to guide me toward the right answer. Thanks much in advance for your feedback. Anna <Hope this helps, Neale>
Re: Albino Cory and fin rot -- 10/18/07
Thanks much, Neale. I will try the medication on my display tank... Though, I am bit worried about my plants ;--( and beneficial bacterias if I do the process in the main tank. <Used properly, modern medications won't harm filter or plants. Just read the instructions carefully, and follow them to the letter.> I forgot to mention that I do clean gravel 2 x a week -- along with water changes (first gravel, than water). I noticed that my pH changes with - or + 0.2 value. That looks like a lot. <Hmm... that's not a dangerous change in itself, but it's the rate of change that matters more. Is this across one week, or six weeks, or what? If on a weekly basis, I'd be slightly concerned, but if over six weeks or more, I wouldn't be too bothered. All aquaria become acidic over time. Water changes reverse the pH drop, and increasing carbonate hardness (KH) slows the pH drop down. For a standard aquarium, a hardness of 5-10 degrees KH should keep the water chemistry stable between water changes. 50% water changes weekly should reverse any pH drops before they become serious.> Maybe I feed the fish too much ;--( <Always a possibility. Review the articles on feeding fish here at WWM or in your aquarium book. As a rule, one or two pinches of food per day are fine, and each pinch should be so small that all the food is eaten in 2 minutes. Catfish should be given their own portion of food, preferably at night. For a small school of Corydoras, a small pinch of sinking pellets or a single Pleco algae wafer per night will be fine.> Perhaps, this may be a reason why my Albino got sick ;--( <Overfeeding compromises water quality; poor water quality causes fish to get sick.> Anyway, I will try Maracyn. Hopefully it will help. <Yes I hope so too; good luck!> Again, thanks much for your help. I greatly appreciate your insights. Greetings from NYC, Anna <Cheers, Neale>
Re: Albino Cory and fin rot 10/20/07
Thanks much, Neale. I got the answer -- I feed my fish too much ;--( The pH changes occur within a week! The cycle becomes apparent -- too much food increases acidity. Water changes drop that factor, which increases again over the course of a week due too increased amount of food in the gravel. I am going to read more about proper feeding. Thanks much for your help. ;--) ANNA <Ah, yes, overfeeding can cause acidification. But also check other factors. Bogwood is a notorious acidifier of aquaria, especially if it hasn't been "cured" properly before use. Anyway, do try halving the amount of food you use, and see how that changes the pH. You might consider adding a chemical buffer to the system to prevent pH changes. Small amounts of crushed coral or crushed oyster shell places in the filter will do the trick nicely. As these dissolve, they raise the carbonate hardness (measured in degrees KH). For a standard community aquarium, you want a KH around 5-10 degrees. In a small aquarium, half a cup of crushed coral should do the trick, perhaps even less. You don't need masses, since you're not after a hard water aquarium like you'd use for a Tanganyikan cichlid tank. But a little extra carbonate hardness, just enough to inhibit rapid pH changes, would be a cheap and effective "insurance policy". Cheers, Neale.>
Re: Albino Cory and fin rot 10/21/07
Neale -- T H A N K Y O U so very much!!! ANNA -- I will follow your instruction. <Cool. Good luck, and enjoy your fish. Cheers, Neale>

Mysterious Sterbai Corydoras Death -- 09/29/07 Hi, <<Good morning, Katie. Tom here.>> I currently have a 10 gallon aquarium housing 4 rosy barbs, four Sterbai Corydoras, and one Panda Corydoras. Tonight when I came home, one of my four Sterba's had sadly passed away. <<Sorry to hear this.>> None of my fish are showing any signs of sickness and the Cory was alive and well this morning when I went to work. <<Certainly nothing that we like to see, Katie, but, with Corys, this isn't particularly uncommon. Their diminutive sizes along with their normal behavior, i.e. lounging on the bottom of the tank, hiding out under plants/decorations, frequently makes it difficult to 'spot' trouble.>> I have had the tank running for a year and all of the fish are the original inhabitants of the tank (cycled before they moved in), except the Panda Cory which I moved into the tank about a month ago (from another tank in my house, which it had lived in for three months). I have no idea why the Cory died as he looked very healthy up to the point where he was, well, dead. Although none of my Cory's are extremely active like other people mention, they do their share of swimming around or lounging on the driftwood in the aquarium. The tank has about 3 watts per gallon of light, but the tank is planted and covered with so they can hang out away from direct light and the lights are on a twelve hour timer. The substrate is sand with a bit of Fluorite mixed in for the plants. I have noticed on all my Corydoras, the barbels are not entirely developed and shorter than the pictures of the Corydoras I find here. (Could this be because of the Fluorite chunks?) <<I consider the notion that Corys 'wear down' their barbels on certain types of substrates a bit of an 'old-wives' tale', Katie. Barbels, almost invariably, deteriorate due to bacterial infections (much like fin rot), not by being worn away on sharp edges of materials. (How long would you walk, haphazardly, on sharp stones in your bare feet before the 'light bulb' went on? Not long, I'm guessing!)>> I am giving you the stats below with the hope that you can help me explain and prevent further Cory loss. Any info you can give would be greatly appreciated. Thanks, Katie Measurements taken when I spotted the dead Cory: Ammonia: 0 Nitrites: 0 Nitrates: 20 ppm <<A little high here given a planted tank. No cause for alarm, obviously, just a bit surprising to me.>> ph: 8 Temperature: 78 degrees Diet: dry flakes at 12 hour intervals (from fish feeder), sinking shrimp pellets, frozen brine shrimp, frozen blood worms (once weekly) <<All looks/sounds pretty good, Katie. One thing that we haven't touched on is water changes. These are largely responsible for keeping the nitrates in check and, digressing back to your nitrate levels, I'm wondering if these aren't a symptom of a problem. Sand, in particular, can trap tiny particles of food and detritus, leading to the buildup of pockets of gas (hydrogen sulfite) which is produced by the bacteria feeding on the trapped solids. This isn't such a problem, if at all, in tanks containing certain varieties of fish such as Cichlids, as a common example, because they sift through the substrate routinely and allow the gas to be vented before it becomes problematic. Your Corys only superficially scavenge at the bottom, however, so they won't be of much help in 'disturbing' the sand enough to avoid this potential issue. Since I keep a fairly large number of Corys of different varieties myself, I can speak to the concern that a lot of hobbyists may have about vacuuming the little rascals up in a syphon tube during water changes. Mine think it's grand fun to dash around the tube looking for goodies that they couldn't reach themselves until I've stirred things up. (They don't listen very well, either!) The upshot here is that between the plants/roots and nosy little fish, you may not be getting the substrate cleaned up as well as it could be. This, in turn, may be creating a less-than-healthy environment for your Corys. (A rather lengthy ramble over something that I'd have passed off as 'just one of those things' if you hadn't mentioned the shortness of the barbels on the other Corys.) Honestly, I can't tell you that this had anything to do with the death of your Sterbai but I think it's something well-worth addressing where your concerns are involved. Hope this helps. Good luck to you. Tom>>

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