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FAQs on Corydoras Cat Disease 3

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,
FAQs on: Corydoras Catfish Health 1, Cory Disease 2, Cory Disease 4, & 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,


Sick(?) Albino Cory    7/1/14
Hello! I was hoping that might advise me. One of my dwarf albino Corys is, I think in some sort of distress. Mind, this little creature has always been rather odd in behavior since I got him about a year ago. He has never grown, for one. He is much smaller than the others.
<Albino catfish are inbred and somewhat weaker than the wild-type; a common problem with albino fish generally.>
The problem I see is that he is either on his back on the bottom of the tank, and I think he's dead!! (until I try to net him out, the he scoots away.) When he is not upside-down, he endlessly cruises the midlevel of the aquarium. He is not bloated, nor does he have any open sores or redness. His breathing is unlabored. He does have an issue with his mouth, though. His barbels are worn away- the others have long whiskers as they should.
<Do review substrate type and how often you clean it.>
He will only come to dinner- kind of- when his best buddy comes over to wake him.
<A clue to one problem -- not enough of them, perhaps? Corydoras should always be in groups of 5 or more. Ideally the same breed/species (Albinos are generally Peppered Catfish so mix with them just fine). But failing that, a mixed assortment generally works okay, too.>
He will snuffle about for a bit, then begin cruising. I never see him actually eat anything. Everyone else is fine and frisky. Is he suffering?
Is he just weird? Should I put him down, or let him be?
<How much and what sort of catfish-specific food are you offering? Quite possibly not enough. Review, and act accordingly. A single Plec wafer for example should satisfy 3-4 Corydoras per night (best time to feed them without competition from other fish) and you should aim to offer them meals 3-4 evenings a week. "Leftovers" aren't enough by themselves.>
My tank:
8 year old 29 gallon low tech

HOB filter and a bubble stone
Moderately planted
Pea gravel substrate with sand "meadow"

Ph: 7.6
Ammonia: 0
Nitrites: 0
Nitrates: 40

Hardness: 100ppm
8 neon tetras
3 Corys
1 young male Betta (quite docile)
6 red cherry shrimp
2 ghost shrimp
a dozen or so assassin snails
I hope I have given enough information... Please advise! He is worrying me, the poor thing!
<Hope this helps. Cheers, Neale.>
Re: Sick(?) Albino Cory      7/3/14

Thank you for the prompt reply!
I will get another albino Cory for a mate. There is one other albino, and 2 peppered Corys, who seem huge by comparison.
<Likely so if they're getting more food. But in any event, this species, Corydoras paleatus, is very variable in captivity, and rarely reaches the full size it does in the wild.>
They don't really hang out with the albinos. Should I get another of each?
<Sounds like a good idea.>
I worry about overstocking my aquarium. Do I have enough room with my small tank for 2 more bottom-dwellers?
<Likely so. Corydoras aren't particularly messy fish.>
The sand is a very recent (2 weeks ago) addition to the tank. It covers just over half of the tanks floor. I added it specifically for the sake of the little ones' barbels. They had to push and shove so hard to get to the tasty bits in the gravel!
<Good exercise!>
I try to drop their food onto that surface for them. I vacuum the substrate weekly, and rake the sand, as I understand you should, every few days. The assassin snails like to burrow through it, as well.
<And likely do an excellent job of keeping the sand clean. Corydoras and Assassin Snails make a good combo -- in fact I have this very combination at home!>
It didn't occur to me that I may be underfeeding. I give them an Aqueon bottom feeder wafer broken into pieces (so they don't all fight over one) most days, an algae wafer about once a week, and a few brine shrimp pellets (everyone eats those) about twice a week. The ghost shrimp and assassin snails also pile onto anything that hits the bottom. Do you suppose, that being so tiny compared to the others, that he may be being bullied off his food?
<Perhaps. Do try scattering small particles. Corydoras will eat all sorts of sinking foods, even, for example, sinking pellets meant for African Frogs. Alternatively, snap wafers into 2 or 3 pieces, and drop around the tank in different spots.>
And that's why he cruises instead of eating- waiting for his turn? Hmmm. I will get him at least one more Cory friend for now, and increase the amount of food.
Thanks again! =)
<Good luck, Neale.>


Possible disease on Cory catfish... again; no data   6/17/14
Hello, I was reading on your site about diseases on cories that look similar to what I observed mine to have and I don't fully understand what it is. There are opaque... sacks is the best work I can use to describe them, on my cories head. One right above its eye, and the other along the vertical ridge of its forehead. It doesn't look like something that could be scratched off (not that I would ever try to) it looks more like part of the fish that is swollen. Does this sound familiar, or would pictures be appreciated. I just need to know how and if I can treat it.
<Have seen such... folks writing in... environmental stress>
The tank has been cycled for a few months now, got over a severe case of Ich that took out the guppies but spared the 2 cories completely. The one with the problem isn't lethargic, it is eating still and shows interest in food.
I can not check the parameters because I lost the color sheet (API freshwater master kit) but all the plants look healthy and I do a ~40% WC every 3-5 days.
<I'd keep this to 25% or so at a time... the vagaries of source water are a concern>
I feed them once a day,
<With what?>

and have a filter that is appropriate
<Meaning what?>
for the tank size,
<Of what?>
and it aerates as well, I also clean the filter sponge every other water change.
Thank you,
Natalie W
<Send data please; maybe a well-resolved pic. Bob Fenner>
Re: Possible disease on Cory catfish... Seven megs... tiny volume, DI water, flake food solamente
I'll attach some photos, he is very active and likes to move around while a camera is pointed at him.
The water I use is distilled water
<... A very poor idea. Fish, life itself does not live in distilled water>

that comes in a gallon jug from a local chain store, it's what I have used for the entity of the tanks life, about 6 months.
I'll cut down the amount of water during the change.
They eat TetraMin tropical fish flakes.
<Need more... Are you able to use the search tool, indices on WWM? The water and gravel here is likely the source of trouble... the latter is too sharp/coarse>

The tank size is very small,
<This too>
it was used for 2 guppies and a catfish. I did not do my research about the Cory when I bought it, and when I learned it was a social fish, I bought another, about 3 months ago, there are no guppies anymore. The tank is 3 gallons.
<Way too small>
What do you want included in the data?
<You've provided it... The environment and nutrition here are your fish/s trouble sources. READ on WWM re.

Thank you,
Natalie W
<Welcome. BobF>

Pygmy Cory with ONE White Spot on Barbell?    6/16/14
Hi! Established tank with normal water parameters
<Need values>
and no recent issues. However, after 20% water change, next morning one pygmy Cory had ONE white spot on tip of one barbell.
<One... not likely parasitic; but trauma>

Quarantined him from the other 4 pygmy Corys, a few shrimp and betta.
Removed betta to a bowl. It's been 3 days now and none of the fish are showing any white spots. And the quarantined pygmy Cory still has a faint tiny white spec at tip of barbell but the bigger white spot is now gone. No other white spots. No medication used. Do you think this is Ich OR ? Wasn't fuzzy. Wasn't rice like. But definitely a larger white spot and he had slight trouble swimming like he knew something was wrong with his barbell.
Now he's acting fine, swimming and eating in quarantine. Any suggestions for treatment?
<To do none>
Can I put him back in his tank? Thanks very much!
<Yes; welcome. Bob Fenner>
Re: Pygmy Cory with ONE White Spot on Barbell?
Thanks Bob! You ROCK. Appreciate your time and help. Have a great day.
<Ah, welcome. BobF>


Corys dying     5/23/14     RMF try
Good evening,
I'm hoping you can help me solve a mystery affliction which is affecting my Corydoras. The first symptom I normally observe is flashing while rummaging around the tank.
<Mmm; Cory's do "glance" a bit naturally... but too much scratching may indicate possibly parasite involvement, and/or something disagreeable with water quality>
This is intermittent, swimming and breathing is normal. Within a couple of days the fish will be unable to maintain balance, will swim wildly spinning and have rapid breathing. The fish will then die (I remove an euthanise at the point of erratic swimming). I have researched online, but cannot find anything which resembles this. I initially thought it might have been that they weren't feeding properly and have changed their diet and feeding regime (and removed the fish which stole their food) and this did improve the situation. I lost 6 of my school of 11 juliis.
After a few weeks with no signs of this problem, I began to restock over a few weeks. A few days ago I observed one of my juliis flashing. The next two days I watched but
I did not see this repeated. Yesterday the julii was swimming erratically so I removed him. This evening I removed a panda who was also unable to swim, but while I was doing this I have noticed two more pandas which I think are going to go the same way. The unaffected cories are schooling all over the tank, eating normally, quite active and exploring the decor and plants as normal.
The only external sign I can see is that I think they are slightly curling to the left. I have looked at the affected fish with a magnifying glass and can see no signs of worms or parasites. There are no red marks on them, gills are normal in colour. Their barbels are all long and pointy and not worn, there is no fungus on the fish and all fins are intact. I can't work out what it is, but it is only affecting the cories, my other fish are fine.
My tank stats are as follows; 150l, 3ft, Eheim 2217 filter. 4 Otos, 5 female platies, 17 neon tetras (disease free), 7 julii cories, 7 panda cories. Substrate is Mr. Aqua soil, tank is planted with Anubias, java fern, crypts and has some floating plants as well. Tank has been established for two years, weekly water change of 30 to 40 litres with weekly vacuum.
Water parameters are;
Ammonia 0
Nitrites 0
Nitrates 0
<Mmm; suspicious. How is NO3 rendered thus? Are you using a chemical filtrant?>

Ph 7
KH 2
GH 9
Fe 0.1 mg/l
<Good to see iron being considered, measured>
My tapwater is Ph 7 with GH 9, KH 0, so I do use some Ph products
<Which and how?>

to stabilise (I have had acid drop before and was advised that the lack of KH was the cause).
<Not here; no>
I use Prime as my water conditioner. I use flourish and excel only on water changes and I mix them into the new water, no additives are added to the tank directly.
I stopped keeping honey gouramis as they would also do the spinning thing, but that was about 6 months before I saw it in the cories and I put it down to the issues with dwarf gouramis.
I apologise for the information overload. I'm so worried about them.
Cories are my favourites and are the reason I have the tank and I don't want to watch them all die in such a horrible way.
Kind regards,
<Strange... am sharing this w/ cohort Neale Monks here for his input. Bob Fenner>
Corys dying     5/23/14        Neale's go

Good evening,
I'm hoping you can help me solve a mystery affliction which is affecting my Corydoras. The first symptom I normally observe is flashing while rummaging around the tank. This is intermittent, swimming and breathing is normal. Within a couple of days the fish will be unable to maintain balance, will swim wildly spinning and have rapid breathing.
The fish will then die (I remove an euthanise at the point of erratic swimming). I have researched online, but cannot find anything which resembles this. I initially thought it might have been that they weren't feeding properly and have changed their diet and feeding regime (and removed the fish which stole their food) and this did improve the situation. I lost 6 of my school of 11 juliis.
After a few weeks with no signs of this problem, I began to restock over a few weeks. A few days ago I observed one of my juliis flashing. The next two days I watched but I did not see this repeated. Yesterday the julii was swimming erratically so I removed him. This evening I removed a panda who was also unable to swim, but while I was doing this I have noticed two more pandas which I think are going to go the same way. The unaffected cories are schooling all over the tank, eating normally, quite active and exploring the decor and plants as normal.
The only external sign I can see is that I think they are slightly curling to the left. I have looked at the affected fish with a magnifying glass and can see no signs of worms or parasites. There are no red marks on them, gills are normal in colour. Their barbels are all long and pointy and not worn, there is no fungus on the fish and all fins are intact. I can't work out what it is, but it is only affecting the cories, my other fish are fine.
My tank stats are as follows; 150l, 3ft, Eheim 2217 filter. 4 Otos, 5 female platies, 17 neon tetras (disease free), 7 julii cories, 7 panda cories. Substrate is Mr. Aqua soil, tank is planted with Anubias, java fern, crypts and has some floating plants as well. Tank has been established for two years, weekly water change of 30 to 40 litres with weekly vacuum.
Water parameters are;
Ammonia 0
Nitrites 0
Nitrates 0
Ph 7
KH 2
GH 9
Fe 0.1 mg/l
My tapwater is Ph 7 with GH 9, KH 0, so I do use some Ph products to stabilise (I have had acid drop before and was advised that the lack of KH was the cause).
I use Prime as my water conditioner. I use flourish and excel only on water changes and I mix them into the new water, no additives are added to the tank directly.
I stopped keeping honey gouramis as they would also do the spinning thing, but that was about 6 months before I saw it in the cories and I put it down to the issues with dwarf gouramis.
I apologise for the information overload. I'm so worried about them.
Cories are my favourites and are the reason I have the tank and I don't want to watch them all die in such a horrible way.
Kind regards,
<Hello Joanne. This is really difficult to diagnose. Water quality sounds fine, and water chemistry is well within the comfort zone of most Corydoras. Given your selection of livestock, I'm assuming you're keeping the tank relatively cool, around 22-24 C/72-75 F, as this suits the Corydoras, Neons, Otocinclus and Platies. Cooler water means more oxygen, and this should be one stress factor we can ignore (in warmer tanks with Angels and Gouramis heat stress can be a problem for most Corydoras species). My gut instinct is that the substrate is an issue here, or rather, oxygen levels. Adding something to keep a brisk current along the bottom might make all the difference. The fact the barbels are healthy is a good sign though, I admit. Corydoras are generally quite tough animals, but you can poison them in various ways (especially airborne toxins, since they're air breathers at times) and as with most catfish, copper is a serious threat if used to treat Whitespot or Velvet. I do think your substrate is a bit rich for a selection of slow-growing plants, and while I would worry about algae problems I can't see the connection with Corydoras except of course they're swimming down there, which makes me wonder. If this was me, I'd remove the Corydoras to a clean, glass-bottomed tank; I'd medicate with something non-copper based, perhaps antibiotics first, then salt/heat for possible Whitespot, and then I'd keep them in that tank for 6 weeks or so, until such time I felt sure they were healthy and feeding.
There are various bacterial diseases that cause problems for Corydoras, such as Red Blotch Disease, but these often have really obvious symptoms, especially red bellies and worn barbels. Yours seem to lack these. That's why I'm tending towards an environmental cause, but there are some protozoan parasites (Rickettsia-like things) that affect catfish that are notoriously difficult to diagnose and with imported L-numbers especially have caused major fish loss. Hope this helps, Neale.><<Mmm; maybe summat to do w/ the substrate toxicity wise; but Corydoras, Callichthyids... are facultative aerial respirators... Low DO should not be an issue. RMF>>

Sick spotted Cory catfish... Ich, no info.
So I recently got 2 baby Cory cats (they're about an inch) along with two lyre tail guppies. Apparently one of the lyres had ick and I've been fighting it the past 2 weeks or so.
<With what? I do hope you've read here:
 My first cory died but his gills looked strange and not very much ick at all on him.
<Armored cats only show such when super-infested>
 Now my females are showing the same odd rainbowness to their gills. My baby is showing it more than my adult female (who was there before the lyres) and isn't as active as normal. Is it ick still or something more serious? My water tests come
back at perfect levels so I'm at a loss. Any help would be much appreciated.
Thanks in advance
<... Tiff; we need more info. Likely the treatment is the real source of trouble here... Your fishes chemically burned. Read the above citation... and the linked files at top. Bob Fenner>
re: Sick spotted Cory catfish

<Add this to your reading list:
I'm using a 15gal tank with a Terra ex filter and heater. I have two fancy guppies a silver lyre tail molly, a sunset platy and my two spotted Cory.
The only fish still showing white dots is the molly on his tail but it could be scaring since white dots haven't changed. No visible dots on the corys just odd rainbow coloring. I've been using jungle ick clear tablets for the last week


Re: Sudden sickness? Panicking... Corydoras... Hypochondria     11/24/12
Hi Bob.  Well I'm still having troubles.  Since I thought the medication (was treating with Maracyn and Maracyn 2) was causing the Corys to have a bad reaction (Albinos swimming frantically, Peppered listless), I decided to stop the medicines for a day, do a 50% water change, and insert a carbon filter.  The next day the Albino Corys were still swimming frantically, but the Peppered Corys showed improvement and were more active.  So I decided to continue treatment with just one medicine, the Maracyn (carbon filter removed).  So in total, the Corys and Honey Gourami had two days treatment of Maracyn and Maracyn 2, one day break, then three days of just Maracyn.  The directions say to treat for 5 days, which I did, but I'm not sure if the 1 day break caused a set back. 
<Not likely much>
The last day of treatment was 7 days ago.  The Corys seem improved; no more frantic swimming, basically active.  The Gourami is more active than before but she is still
spending a lot of time on the bottom of the tank, in corners.  I noticed she looks slightly swollen in her abdomen.  When she is on the bottom, she sometimes has her head down and tail up (although no longer leaning to the side, which she was doing prior to medication).  Before she had some stringy feces, but they were not white (they were green).  Her feces now look normal.  So I'm thinking the Maracyn may have helped a little bit, but hasn't cured her.  I'm leaning towards Hexamita, even though her feces aren't white.
<Which the Maracyn products won't treat>
  I considered dropsy too, but she isn't grossly swollen, and her scales are not protruding.  She is still eating, but mostly the sinking pellets; she isn't noticing the flakes at the top of the tank (unusual).  And while eating the pellets, I noticed today she kept swimming to the top of the tank to take quick breaths.  She is also still acting skittish.  But, considering the Hexamita, I don't see any thinning on the top of the head, no holes or lesions,
<Might just be lumenal, or sub-clinical>
 and she is not swimming backwards.  So, with the symptoms she does have, would you recommend treatment with Maracyn 2 or Metro?
<The last>
  As a side note, 9 months ago I had a Guppy in his own tank who became afflicted with Hexamita.  I treated him with Metro and he seemed to have recovered, but then passed away a month later. 
<Mmm, could be... most anything. But Metronidazole is quite toxic; should not be repeatedly applied>
I was careful not to cross contaminate.  I was also curious if the dead snail could have infected the fish with anything (I've heard a lot about the parasites snails carry).
 On another note, the tank is still barren, except for 3 live plants (Anubias, java fern).  Thanks for your time and input, Lorie
 Re: Sudden sickness? Panicking...    11/24/12

Hi again.  I checked on the Gourami right after I emailed you and she seems worse.  She's sitting on the bottom still, but now she's breathing hard.  And she is leaning a bit after all.  So i did a water change (which uncharacteristically scared her), and decided against Hexamita after all and began treatment again with Maracyn 2.  I decided this because when I treated her before with Maracyn 2, she showed some improvement.  Since she doesn't have the stringy feces or loss of appetite, I concluded she has an internal bacterial infection.  Well anyways, I'll see how she does/if she makes it by morning.  Thanks, Lorie
Re: Sudden sickness? Panicking...    11/24/12

Never mind Bob. I did another water change then treated with the Metro. If the Gourami shows improvement, then I will try to feed her the Metro as well. Thank you for your patience and help. -Lorie
<Glad to share what I can. B>
Re: Sudden sickness? Panicking...    11/24/12

Thanks for your reply.  Well I already treated with Maracyn 2 last night, and this morning the Gourami is the same; sitting at the bottom, breathing hard.  She's swimming a bit too, but she'll swim up and down, almost in a straight line, with her nose to the glass wall; I don't know if that tells you anything, it just seems, neurotic maybe?  Or she's unsettled.  This is so discouraging.....since I already treated with Maracyn 2, what would you recommend at this point?  Thank you, Lorie
<Perhaps the default dual treatment (four additives) of Metronidazole and an Anthelminthic... B>
Re: Sudden sickness? Panicking...    11/25/12
Hi again and thanks. So I'm treating the water with Metro, and I attempted to feed with Metro too. I read an article that said you can bind the Metro with dry food using fish oil; it kind of worked. I believe the Gourami got some medicine in her. I'm going to try to bind medicine to the sinking pellets for the Corys. As far as the anthelminthic medicine; is salt a viable option?
<For treating for worms? No>

If I use salt, do I raise the temp of the tank?
 Should I vacuum the gravel since the fish ate the Metro, and since they will receive another antiparasitic medicine?
<I wouldn't increase the regular maintenance>
Or is another medicine a better option than salt? The Mardel line recommends Coopesafe
for parasites, but is that safe for Corys?
<... is too toxic and unneeded. A timely note: MANY more captive aquatic specimens are killed by mis- and over-treating than from pathogenic disease. BobF>
Is there a specific medicine you recommend if salt isn't a good idea? I have a 10 gallon tank, 1 Honey Gourami and 5 Corys. Thank you! -Lorie
Re: Sudden sickness? Panicking...     11/25/12
Maybe I misunderstood; in your last response you recommended a dual treatment of Metro and an anthelminthic drug. That's why I was asking about salt or a recommendation for an anthelminthic drug. -Lorie
<... no; Please learn to/use the search tool, indices on WWM. Read here:


Corydoras dying  - 10/22/2012
Hello. I've been having this fairly recent problem with what started as a school of 8 mixed Corydoras (two skunks, two julli, two elegans, two false bandit).
Around July I lost a skunk Cory, a week later the other skunk died. I wasn't sure if that was just a fluke.
Then about a month later it was a julli, and now just a week ago I noticed one of the false bandits surfacing a lot, and resting in my floating plants, emaciated and not looking very good.
I noticed his fins were torn,
<What other livestock here?>

 so I set up a large clean container, put an airstone in, and put him and the other false bandit (also torn fins, no barbels) in there, treating with MelaFix and PimaFix combined,
<Worthless; search WWM re>

 at least for the sake of the second one. The very sick one was laying on his side at first, and the next day I checked and he was sitting upright.
On the third day he died, but I continued treatment for a week for the second one, hoping to help with torn fins. After I saw some regrowth I eased him back into the 55. I noticed he was breathing rather rapidly, but I figured it was just from the whole acclimating deal. Yesterday he was active, until he swam up and rested in the same spot of plants the other one did. Today I found him dead by the filter. That was the only one who didn't show the usual symptoms, besides not really eating.
Symptoms include lethargy (even for a Cory), no interest in food, and eventually they get skinny and die. Not all of them have had torn fins. The tank was started last December and is a 55 gallon stocked with the 3 remaining Corydoras (2 elegans, 1 julli) 8 neon Rainbowfish, 10 harlequin Rasboras, 6 Madagascar Rainbowfish, 5 zebra danios, 1 Bristlenose plecostomus,
<This Ancistrus may be the root of trouble here>

3 banded mountain loaches, 5 Kuhli loaches, 1 survivor Oto, 1 dwarf gourami, 5 gardneri killifish, 3 flower shrimp and 1 Rhinogobius wui/duospilus that I'm trying to move to his own 10 gallon. Ammonia and nitrites are at 0ppm, nitrates under 20ppm.. The pH sometimes fluctuates a little during water changes because we have very hard city water, and the driftwood in the tank ends up buffering that to around 7. Temperature is at a consistent 75 degrees Fahrenheit. The tank is planted, with dirt capped by gravel. (I know gravel's a no-no for them, but I wasn't aware at the time of buying them of how detrimental it could become) I do weekly 15-20% water changes.
At first I suspected the banded mountain loaches were hogging the food, because they're quite voracious eaters, squabbling with each other and guarding their food, but I'm making sure the cories are getting some I feed algae wafers, shrimp pellets, frozen bloodworms, frozen brine shrimp, and frozen glassworms. When I have the worms out, the elegant cories will eat from my fingers, so I feel better about that. Not sure of the best way to treat my remaining 3, because I'm fairly positive it's only a matter of time. I'm thinking parasites at this point, but what would you suggest using or trying?
<Removing the Loricariid or the Callichthyids to elsewhere... separating them. Someone, something is beating on them...>
 But then if it were parasites, wouldn't my other fish be showing symptoms?
<Likely so; yes>
 Everybody else has been seemingly healthy. Even the cories, though they aren't terribly active, have little full bellies until their last week.
Advice is greatly appreciated.
<I have experienced such troubles myself twixt these catfishes... Some "Plecos" will "ride" other fishes... cause them health issues by sucking off their body slime... Bob Fenner>
Re: Corydoras dying     10/23/12

I don't really think it's the plecostomus,  because he tends to stay on his driftwood,
<Not during the night; this is when they're most active>
 but I don't think it'd hurt to move them and see what happens.
Wouldn't there be some kind of visible evidence on the fish if that was the case?
<Mmm, yes... the torn fins you mention, a lack of body slime and what it portends... infection, death>
 I wondered if Corydoras have some sort of specialized disease, like dwarf gouramis can get "dwarf gourami disease", or how neon tetras can get "neon tetra disease". But I haven't heard of it. Just a thought.
<Corydoras do die more easily given some types of stress, conditions, but no specific pathogens as far as I'm aware>
Do you think I should move the three into my recently cycled (started on Oct 2. It cycled quickly.), heavily planted ten gallon and see how that goes?
<Yes... with a good deal of the current water, perhaps a bit of "mulm" siphoned from the older tank's gravel>
 Right now it just has one Danio. She's my 'ammonia source' for now.
There IS small gravel, for substrate, but oh, well. Wasn't planning on more cories, because I've just had the *best* luck with them.
If it so happens that there's an internal parasite involved, what would you treat them with if it comes to that?
<... would depend on its diagnosis, identification. I myself would not simply "blast treat" w/ anti-Protozoals, Anthelminthics et al. w/o knowing what I was treating. BobF>


Corydoras aeneus missing eyes - 10/21/2012
Hi Crew, James here.
<Rick with you today.>
I have used your site over the years and it has come to be my absolute favorite resource for all things fish related.
<Mine too!>
The consistency and expert level of advice is something not offered by and other site as far as I can tell.
Anyway, on to my question. This morning I purchased six Bronze Corys (Corydoras aeneus) from my local store, although actually we paid for 5, the sixth was free on account of his 'issue'.
<Ah good, they are schooling fish.>
He has absolutely no eyes, just sockets. He seems extremely healthy and happy, zooming around and digging in the sandy substrate with his buddies.
These fantastic catfish are in a 180 litre aquarium that has been stocked for just over a month, having been cycled using a live bacteria product.
Today's test shows 0 Ammonia and Nitrite, a Nitrate of roughly 10, moderate hardness (according to your table), a pH of 7-7.2, and a steady temp of 24C. The other inhabitants are 11 Silvertip tetra (Hasemania nana), and 2 very small Ancistrus sp.
As far as feeding these guys goes, we feed a high quality flake twice a day, and will be feeding catfish pellets 3-4 times per week after lights out. I will also be picking up some frozen food, hopefully to get the Corys into breeding shape.
So, really, my question would be are we doing everything these little guys need, particularly the blind one (now called Stevie, aka Stevie Wonder. I know, I know)? Should I be feeding him differently to the others, making sure he is eating? Also is there any chance other fish might pick on him more? We are all quite attached to our little rescue fish!
<I would treat Stevie the same as you treat all the other Corys as long as he remains healthy and active.  I doubt the tetras will bother him. In my experience, tetras couldn't care less what is going on down at the substrate.  Plecos like to stay to themselves. There may be some bullying over food, but that can be minimized by dropping pellets/wafers in more than one spot.>
Any further advice would be much appreciated
Re: Corydoras aeneus missing eyes    10/24/12

Thanks very much, I have no doubt now that he will be just fine!
<You are very welcome. Let us know how he does. - Rick> 


Julii with odd infection.     5/29/12
Hello Crew,
I noticed today a Corydoras Julii with a strange milky white/pink growth at the base of it's right gill, seeming to protrude from the front of it's pectoral fin.  It was spherical in shape, and approx 3/32" or just under 2mm in diameter. 
<Have seen such a few times>
I was unable to pin down exactly what it might have been via the Freshwater Disease Troubleshooting table, or by searching, although I may have not been able to find the correct words.
Tank Info: Freshwater, 75 Gallon AGA, 40 Gallon Sump. Total Water Volume 100-110 Gallons, (Lose 10 gallons/week to evaporation between water changes). Finished cycling 1 month ago
<So very new>
 using 10% Ammonia solution.  20% water change every Tuesday.  Mechanical Filtration via filter wool, biological filtration via Kaldness K1 fluidized.  Return pump turnover 500 GPH, enters display via spray bar which runs the entire length of the front of the aquarium, mounted at the top pointing down.  Four lamp T5HO 6500k 216W lighting Micro Swords, Unidentified Amazon Sword, Java Ferns, Bronze Wendtii, Java Moss (confined in plastic mesh pyramid), and Wisteria.  Sand substrate, plastic decorations (rocks, log, roots).
Water Parameters: Ph 7.5, Ammonia 0ppm, Nitrite 0ppm, Nitrate 0-5ppm, GH/KH 6 degrees/4 degrees (All measured with API liquid drops, not test sticks), Temp 22.5-23.3 depending on lights on/off.  Water changes using tap water, treated with Seachem Prime.
<All right>
Stocking: 7 Corydoras Paleatus, 5 Corydoras aeneus (not albino), 7 Corydoras julii, 2 Otocinclus
Feeding: Twice daily, rotate through Hikari Sinking Wafers, Aqueon Shrimp Pellets, Hikari Sinking Carnivore Pellets (sparingly), and Frozen Brine Shrimp twice weekly.  (Paleatus spawn within hours every time after being offered Brine Shrimp).
The fish in question has been in the Display for 2 weeks, purchased from LFS 4 weeks ago with 11 more, lost 5 during quarantine for reasons still unknown to me, although they were all in pretty rough shape when I received them (appeared underweight, virtually no barbels).
<Too typical... poor housing, treatment ahead of your acquisition>
 I haven't noticed any similar problems with any of the other Julii's, or any of the other Corydoras.  To me it seems likely this is either a fungal or bacterial infection at the site of physical trauma.
<I do concur>

 I can't say how the fin/spine could have been damaged unless it was damaged during transfer from QT to DT and the infection is just now becoming apparent.
Pictures Here: http://imgur.com/a/1j13O#12
<Not attached>
I tried to get pictures in the display, but it was proving difficult, I did get one that was clear enough to give an idea of the growth.  The blister/sac popped/collapsed shortly after the fish was placed in the 'photo studio' but I was able to get a few shots of different angles of the affected fin, and the remaining sac, as well as what was expelled form it when it was punctured/popped (The brown ball of crud seen in a couple of the pictures).  During this time I also noticed a white/grey protrusion on the front of the face, almost directly between the nostrils, clearly visible in the head-on pictures, and the silhouette can be seen in a couple of the side shots.  I'm not sure what to make of this...worried that it could be a parasite.
<Not likely at all... I would not treat, do anything other than good care here.>
I'd really appreciate your expert input on these, as far as pinning down what the problems actually are, potential causes, and what steps I need to take to remedy them.
Checked tank again before hitting send, the Julii in questions is swimming/behaving normally, although the remains of the sac are trailing along side him as he swims.  Paleatus are currently spawning.
Thanks Much,
<Not to worry. This incident will pass, heal on its own. Bob Fenner>

Re: Julii with odd infection.      5/29/12
Thanks much, my error with the pictures.  For the sake of completeness I picked the two most relevant, re-sized, and attached.
<Thank you for sending these along... Does appear to be like what I've seen before... amorphous, acellular, apparently "pus filled" sac... And again, I'd just ignore... these almost always resolve on their own sans "treatment/s". BobF>

Plump Cory Cat with Strange bumps on Back (RMF, any other ideas?) <<>>    5/6/12
Hello.  Over the past four days or so, I have noted that one of my peppered Cory cats has become almost obese.  I wrote it off as the fish being gravid at first.  (I have seen one of the other peppered Cory cats swim up to it (maybe her) and form the "t" shape.)  Now, I have noticed something strange.  First, there are clear(ish) bumps on its back near its dorsal fin with about three bumps on each side.  The bumps resemble eggs, but I highly doubt eggs got could get on its back.  Next, the Cory cat's eyes seem to be bulging out more than normal.  None of the other fish show any symptoms.  I haven't seen anything like this before.  These are the water quality parameters:  Ammonia 0 ppm, Nitrite 0ppm, and Nitrate about 7ppm (between 5 and 10 ppm).  My best guess is a fungus, but I can't find anything that resembles this.  Thank you in advance.
<Hello. I have seen this, though usually in older specimens at least 3-4 years of age. I'm not completely sure what's going on, but if these are the same puffed-up "boils" that I've seen, my best guess is that we're looking at a bacterial infection of some sort. It may be some sort of Aeromonas, Pseudomonas or Mycobacteria infection,
<<Or other/Protozoan involvement>>
 but in any case, I think it's brought on by an environmental shortcoming of some sort, likely lack of oxygen at the bottom of the tank, excessively high water temperature (which exacerbates problems with oxygen availability), and an insufficiently clean substrate. Let's review. Almost all Corydoras come from relatively cool streams, and do best at 22-24 C/72-75 F. This is a shade cooler than we tend to keep Southeast Asian fish like Gouramis, but similar to what Neons enjoy (and doubtless overheating Neons is one reason so many people fail to keep Neons alive for long, but that's another story). The warmer the water, the less oxygen it holds, and because Corydoras swim at the bottom of the tank, they're furthest away from the oxygen-rich layer at the top that sits next to the air. Furthermore, many filters are very bad at getting the bottom level of water moving at all, and that means the oxygen concentration at the bottom of the tank is well below what it is in the middle and upper levels. Undergravel filters, ironically given their poor reputation these days, were pretty good at fixing this problem because by definition they drew the bottom level of water up to the top of the tank with each cycle of water movement. But hang-on-the-back filters and canister filters are less good (and sometimes very poor) unless configured properly, with the intake close to the bottom and the outlet at the top where air and water can mix. Put some flake at the bottom of the tank -- if it sits there without moving, then lack of circulation is one problem that needs fixing! Check the thermostat too, and unless you've got one of the few "hothouse" Corydoras (Corydoras sterbai is the only commonly traded example) then you may need to turn the heater down a degree or two.
Finally, check the cleanliness of the substrate. You should be stirring it once or twice a month, siphoning out any detritus. Malayan Turret Snails will do this for you automatically, but not everyone wants these fast-breeding snails, in which case substrate cleaning duty falls to you.
Why does this matter? Partly because decay in the substrate uses up oxygen at the bottom level of the tank, but primarily because rotting organic matter breeds bacteria that seem to trigger all sorts of problems in Corydoras: erosion of the barbels, sore and red bellies, and of course this boil-like disease that we're discussing here. Incidentally, if your Corydoras has a red belly and/or short barbels (they should be around 1.25 cm/0.5 inches long on an adult, and very tapering rather than blunt and rounded at the tips) then you can be even more certain the problem is an environmental one rather than anything else, with bacteria merely translating the problem into what you can see on your catfish. Cheers, Neale.>

Re: Plump Cory Cat with Strange bumps on Back (RMF, any other ideas?) - 5/8/2012
Thanks for your reply. If I were to lower the temperature (78 F),
WWM: Still too warm. Do see last message. Then go visit a site like PlanetCatfish.com or SeriouslyFish.com to look up the specific temperature range for your Corydoras species. For the common species, like Bronze and Peppered Catfish, we're talking 22-25 C/72-77 F (a few, like Bearded Corys, need to be even cooler). The warmer you keep them, the shorter they'll live, and the more prone to problems. Kept at the right temperature, farmed Corydoras live for about 5 years, though older specimens are not uncommon. If your catfish is only 2-3 years old, then old age isn't likely the problem.
would further measures need to be taken, like medications?
WWM: For sure. Antibacterial medications of some sort, at minimum.
I vacuum the gravel every week, and my flakes, if they do reach the bottom (greedy swordtails) do "blow" around.
WWM: Good.
This fish is the oldest of the Cory cats, so as you said age may also be a factor.
WWM: Indeed. But do be open minded, and review the aquarium.
Once again, thank you. Oh, I have an angelfish in the same tank; would it be ok with a lower temperature? I know they like high seventy to low eighty degree water.
WWM: Angelfish are compatible with "hothouse" Corydoras species like Corydoras sterbai, which can tolerate temperatures up to 28 C/82 F. These are the classic choices for Angelfish and Discus set-ups. Hmm… what else… would rate Brochis as better choices for use with Angelfish in any event.
WWM: How interesting.
Cheers, Neale.
Re: Plump Cory Cat with Strange bumps on Back (RMF, any other - 5/7/2012
ideas?) What I meant was that the current temperature is 78 F, and I was thinking about lowering it to 76 F.
WWM: Real good. Do check this is compatible with any tankmates though.
Yes, I once had a Cory cat live to be eight years old at 68 F. I have a Brochis as well. Once more, thanks for your help.
WWM: Glad to help.
Cheers, Neale.
Re: Plump Cory Cat with Strange bumps on Back (RMF, any other ideas?) - 5/7/2012
Thanks for your reply. If I were to lower the temperature (78 F),
WWM: Still too warm. Do see last message. Then go visit a site like PlanetCatfish.com or SeriouslyFish.com to look up the specific temperature range for your Corydoras species. For the common species, like Bronze and Peppered Catfish, we're talking 22-25 C/72-77 F (a few, like Bearded Corys, need to be even cooler). The warmer you keep them, the shorter they'll live, and the more prone to problems. Kept at the right temperature, farmed Corydoras live for about 5 years, though older specimens are not uncommon. If your catfish is only 2-3 years old, then old age isn't likely the problem.
would further measures need to be taken, like medications?
WWM: For sure. Antibacterial medications of some sort, at minimum.
I vacuum the gravel every week, and my flakes, if they do reach the bottom (greedy swordtails) do "blow" around.
WWM: Good.
This fish is the oldest of the Cory cats, so as you said age may also be a factor.
WWM: Indeed. But do be open minded, and review the aquarium.
Once again, thank you. Oh, I have an angelfish in the same tank; would it be ok with a lower temperature? I know they like high seventy to low eighty degree water.
WWM: Angelfish are compatible with "hothouse" Corydoras species like Corydoras sterbai, which can tolerate temperatures up to 28 C/82 F. These are the classic choices for Angelfish and Discus set-ups. Hmm… what else… would rate Brochis as better choices for use with Angelfish in any event.
Sent from my iPhone
WWM: How interesting. Cheers, Neale.

Eyesight of Corydoras and other advice, env. 4/7/12
Hi there WWM Crew,
Your website has been of great help to me when I had a pair of Bettas. I'd never thought I would actually email you to consult some of your wisdom, but here I am.
I am playing with a self sustaining tank (or partially self sustaining).
Actually let me rephrase that, a self sustaining 1-gallon jar.
In said jar, I have
1 Ramshorn snail,
2 Malaysian trumpet snails (and their various off springs)
1 Corydoras aeneus
<Needs more room, filtration...>
3 ghost shrimp
1 large Anubias plant (not sure of the species)
1 Anubias nana
Some crazy elodea that needs constant pruning
<Likely E. canadiense>
Water wisteria (which is also crazy and needs pruning) Java fern hitch hiker that is now growing daughter plantlets a banana lily which I just de-leafed since it was getting lanky banana lily leaf left floating that is growing roots random strands of java moss that probably hitch hiked on the Anubias Various masses of micro fauna (Cyclops, daphnia, other mini crustaceans, worm and Planaria)
Algae that is constantly being munched on 3 seashells as water buffer
The substrate is about a 1/4-1/2 inch of sand + scattering of gravel.
plants are planted in measuring caps (with holes drilled) and gravel, just to keep it neat.
Tank gets 12 hours of light a day from a 100w cfl that I turn on for all my plants. The larger Anubias is sprouting its third leaf in about 2.5 months, probably due to the bright lighting. There is no filtration or aeration.
The lid is kept on the jar at all times.
I have never measured my water parameters, starting this whole thing of as a simple experiment and really just wanting to keep underwater plants. The tank has not had a water change since its setup at around a month ago, and since the ghost shrimps are going along swimmingly, I will avoid putting a hole in this poor students wallet and forgo test kits for now.
The original inhabitants at the top of the food chain were feeder minnows, all which succumbed to fish tb (apparently a local Petco epidemic in their feeder tanks right now, the feeders have yet to be restocked), I removed all three fish from the system after they began to show symptoms (kinky spine, floating to top, skinny but sill feeding well).
After the minnows went, I noticed that the mini critter population boomed, and figured that I need to re introduce a fish. I researched for a small hardy fish. This turned out to be the bronze Cory cat. I was hesitant to get the Cory cat being afraid that it will become lonely. However at Petco the other day, I saw this little one bumbling about, very active and decided I would give it a try.
After a week, he is absolutely fine and bustling about as usual, his barbels are growing longer! =D . but I noticed that from the time of purchase that he doesn't seem to see me when i put my finger against the glass right in front of him. in fact there is no reaction at all, he will simply continue to do what ever he is doing. I know the glass is clear as the old minnows used to greet me when I came past and excitedly rush up and down the glass for their food. Do you think its possible the fellow is blind?
<Yes... environmental...>
In Petco he was kind of a lonely guy and the only one that explored the entire tank rather than just the bottom. I studied his eyes and they look fine and not cloudy. I also noticed that when i drop in a bit of a sinking wafer for him, he doesn't know its there until he finds it with his snout, even though it should be in his line of vision.
Other than that, he seems a happy fish so far. The system seems to be able to sustain him as of now, I'm going to let it run for another month with just him to see how it handles the eventual waste buildup. If the tank thrives, I will take a risk and get him a friend. If it doesn't I'll invest in a 10gal for him and get a few more Corys.
I would love to hear any extra advice you would have for my tank as well!
<A neat experiment... have a friend in Hawai'i who makes sealed glass spheres... w/ naught but a Neocaridina shrimp, algae and a sprig of gorgonian (and seawater, a bit of air space); and have seen sealed systems over the years>
Thank you for your help!
<I encourage you to write up your spec.s, observations and submit them for publication in pet-fish e- and pulp zines. If you'd like, I will help you to offer the work to editors. Bob Fenner>

Re: Eyesight of Corydoras and other advice     4/10/12
Hi bob!
Sorry for the delayed reply, I was caught up with my small mountain of school work.
One night, as I was pulling an all nighter, I neglectfully left the lamp on the tank for 24 hours. The algae grew as if they were on drugs!
<A clue!>
Other than the plants (especially the Anubias) the rest of the tank cant be happier. The Cory cat wont stop eating! you cannot imagine how fat his little pot belly is right now. Im a little worried he might eat himself to death.
Speaking of my boast about my ghost shrimps surviving on month, one died a few days ago, right next to his newly moulted shell. I couldn't figure out the reason of his death. the shell was completely shed and his body was lying right next to it. I left it in the tank anyway to see how the system will handle a death. I did throw in a long stalk of lucky bamboo to help with the ammonia absorption. No problems so far it seems.
<Mmm, needs to be tested>
I also threw in a piece of banana leaf to see how it will impact the system. Nothing so far other than a mildly yellow colored tank.
Thank you for offering to help me with keeping a diary on this 1gal tank but Im not sure if this crazy schedule of mine will permit any reliable updates :( although I am quite excited about how this little jar is going along.
<Ok; perhaps later>
You never answered my question about the bronze Cory. I am just curious about the overall eyesight of the species and whether its possible that this one is blind? (being unreactive to curious fingers again the glass etc)
<Yes, is possible... from environmental stress... the nutrient levels are likely sky high. I'd check Nitrate... as a window here>
Thanks again for reading!
Here's a couple of photos of the system and its inhabitants.
One of the trumpet snails, see if you can  spot the ghost shrimp!
crazy plant needs pruning
The little guy is taking one of his rare breaks
A week ago
<Thanks for sharing. BobF>
Re: Eyesight of Corydoras and other advice     4/11/12

My goodness, fast reply as usual!
Thanks for the heads up on the nitrates, I've read somewhere that plants absorb nitrates slower than ammonia.
<Ah yes; for the most part, this is so... and not widely understood>
 Didn't pay it much heed since I believed that the excessive amount of plants will nuke all ammonia.
<Mmm, no; not necessarily the case>
 will get the water tested soon (at the LFS)  and update you guys with the readings :) Thanks for the advice! maybe the little tank is in need for a water change!
<"When in doubt, water changes". B>

Yes, a glass jar; sealed


Difficulty to identify the problem with my habrosus   4/1/12
Hi, I apologize in advance for any mistakes, English is not my mother tongue)
<Not a problem.>
I hope you'll be able to help in this, my habrosus are ill and it seems at least one of my guppy has gotten sick too. It is a 15 gallons tank (the base is 30.5 cm x 60.1 cm).
There are a clown Pleco (Peckoltia vittata - the smaller kind) and two rainbow fish (Iriatherina werneri). They are in there for quite a long time now. we thought to add some life in it so we buy : 1 Endler male and two female plus 8 habrosus. (and now lots of tiny babies).
We put them in a quarantine tank for 40 days (I prefer to add it as it seems not everyone use 40 days…).
<Ah, the original meaning of "quarantena" I believe…>
40 days later all is well and we add the whole bunch in there. Keep an eye on ammonia, nitrite and nitrate: there is lots of plant in there : java fern, java moss, Hygrophila.
A few days later I notice one of the habrosus flashing against the gravel... but not so often. As there was no ammonia, I thought it might be the stress and let it there.
When he began swimming upside down... and not just at the surface but like all the time, I check my water parameters: still nothing (to my eyes, of course) and as I didn't want to contaminate all the other AND I didn't want to let him suffer, (he was lying on his back on the gravel, breathing heavily) I take him out.
now there are three others with the same symptoms. What is troubling is: they keep being active and eating and then they began swimming weirdly. One of them is really in a terrible state.
my hypothesis thus far:
- Temperature: we have a warmer weather recently and the temp. rise to 82F, since then I lower it (very slowly) to 78F. After what I've read, it seems too high.
<Yes, but shouldn't cause major problems. But can make a bad situation worse. Do increase aeration if possible. Or remove some water (maybe 20%) and add colder water to the tank. You can even float ice cubes in the water!>
- The mulm forming with the wood and the Peckoltia: there's always some kind of dark waste. I'm doing a 2 gal water change every week (regular base) and keep vacuum it but there's always a little bit of it under my java moss. The habrosus kept hiding in this kind of spot, could it be there's an harmful bacteria? I've taken out almost all my Java moss since then, to get rid of it.
<Unlikely a problem. Corydoras LOVE mulm!>
So now, after all those changes (on three weeks, to not stress them and with no medication as I don't want to treat without knowing what I'm doing), there are still sick habrosus and now, the male Endler is doing the same weird swimming pattern.
There's not Ick, no exterior sign of illness, apart from a slight redness at the gill of the habrosus... So I don't know…
<Ah, now, I think either Ick or Velvet are very definitely "suspects" here.>
So here are the water parameters : pH: 7.2, ammonia: 0, nitrite: 0, nitrate: 0, phosphate: 0.25
<Sounds good.>
I'm thinking about buying Prazipro, as, after reading your site, it could be velvet... But I am very reticent to treat not being sure it might be this... On the other hand, I don't want to see all the fishes dying too.
<Hmm… would try the salt/heat method first...
Or else a catfish-safe Velvet/Ick medication; I've found eSHa exit safe with my Corydoras. It's inexpensive and widely sold in Europe.>
Thanks in advance for anything advice! I hope I didn't forget any information.
<Cheers, Neale.>

Re: Difficulty to identify the problem with my habrosus    4/12/12
Hi Neale,
Thank you for the quick answer and sorry that I haven't answer back sooner. I wanted to be able to update on the situation.
I am trying the salt method... and although the habrosus are not flashing anymore, they're swimming "funny" which means on the back or not even swimming anymore… I've lost two and now I've noticed two others swimming in this strange way.
<Not good. Salt at 2 g/l shouldn't cause undue stress, but do keep an eye out. Corydoras are sensitive to warm, oxygen-poor water. If you can, improve aeration. Also try lowering the temperature. Yes, salt/heat is the treatment for Whitespot, but lowering the temperature to, say, 24 C won't slow things down that much, and the treatment should still work within 2 weeks.>
I'm keeping the treatment for two weeks, but mostly to keep my other fishes away from harm, whatever it is that had happened to the habrosus… I have to admit that I am now resigned to lose everyone of my little cories... I don't think I will add others as I didn't find out what harm them... the fact that they're swimming this way making me think it is not velvet in the end.
<I agree.>
On the "plus" side, my endler male is swimming correctly again but I am keeping an eye on him.
And I am going to upgrade my filter from an aquaclear 20 to an aquaclear 30 (for a 15 gal). I won't take any chance and with all the tiny babies, even if I don't have any sign of ammonia or else, I will play on the safe side.
Thanks again for the help.
<Sorry things haven't improved so far, Neale.>

Re: (Guppy Stringy Poop) Peppered Corydoras, Other Factors? 1/24/12
Hi Neale. My Peppered Cory passed last night.

<Too bad.>
I had him under 6 months.
<Can live much longer. I have one swimming around that's about 6 years old.>
I understand what you are saying regarding temperature and respiratory distress. I thought if Cory's could tolerate temps up to 77 F, that 78 F would be okay- but you're saying that Peppered Corys require a much lower temperature.
<Require? Well, they're adaptable. But prefer? Yes, coolish sorts of conditions, like you'd offer Platies, Danios and Neons work best; 22-24 C/72-75 F for all these fish is the ideal.>
I noticed other things about my tank though, and would like to throw these ideas out to see if they may be related factors. 1. As a whole my tank does not accumulate a lot of algae. What algae there is, I clean every week to every other week. I have this one fabric plant that I hadn't cleaned in about 3 weeks. I noticed the accumulation on this plant was the color black- I'm assuming algae and tank "muck". It did not clean off well with a brush, so I decided to soak it in a weak bleach solution for 30 minutes. Then I tried scrubbing the plant again, and still the black was difficult to remove- it reminded me of black paint. Could this accumulation be toxic to the fish?
<In and of itself, algae, even Black Beard Algae and Hair Algae, isn't harmful. Bleach could be, of course, and I would never use it. Hydrogen peroxide is a safer bet if you really want to blitz something, but do bear in mind that if something has algae today, and you clean it, it'll likely have algae all over it a week from now. Algae is caused by an environmental problem, and if that problem remains, the algae will be back. Do read:
and the linked articles.>
I do 25% weekly water changes and ammonia and nitrite are zero, nitrates up to 20 ppm. 2. I noticed on the rubber parts of my heater, "red" algae accumulates. Is this harmful? Thank you- Lorie
<Unlikely. But blue-green "algae" (which may be red or black, as well as cyan, blue, green, or purple) is indicative of poor conditions. I've usually seen it in tanks that are overstocked, under-filtered, overfed, or with too little water movement. Blue green algae seems to thrive in regions with poor water flow, and that will likely mean little oxygen, and that in turn is VERY harmful to bottom-dwellers. Reflect, investigate, and act accordingly. Cheers, Neale.>


Corydoras sterbai issue (Bob, any ideas?)<<>> 12/7/11
Hello team!
It's the first time I write to you and I have read almost every post in your website regarding "infections(?)" of sterbais.
<Fair enough.>
I have 3 sterbais for almost a year now in a 10gal aquarium.
<A trifle small for these, but not the cause of the problem.>
I also have plenty of Java Moss and 3 snails for the algae. Water temperature is steady on 26.5C and I use a sponge/carbon filter with embedded air supply. Water conditions are at very good levels with no ammonia (0ppm), nitrate (.21ppm),
<<Is this Nitrite? If so, toxic>>
or PH (8) issues.
<<Really too high>>
I do water changes every 3 days at 20% per time.
<I see.>
However, over the last two months, one of my sterbais is developing something like a tumor between his eyes,
<Yes, I see.>
although he hasn't lost his appetite (I feed them with catfish wafers - Tetra Wafer Mix ) but he lacks of activeness. I have tried an antibacterial medication with Acriflavine because I strongly believe it's bacterial related infection, but no luck.
<I don't. I actually think this is either viral or environmental, and most likely the former, though environmental stress, e.g., from a mineral toxin such as copper, may have allow the infection to get started. My thinking here is that this is something like Fishpox in Koi or Lymphocystis in Perciform fish.>
It seems to recede for a few days but it spreads again.
<Yes, very viral.>
I have attached a few pictures to see what it actually looks like. Can you please give me any hints of what might be the problem and possibly any solutions? I really want him to live for a few more years'¦
<The thing with viral infections is that treatments, even for human viral infections, are pretty minimal. Basically, this fish can recover under its own steam given good conditions and a balanced diet. But viral infections can take an extremely long time to heal, months even, and they can come back years later. You can probably assume all the fish have been exposed to this virus by now, so removing it would be pointless. But do ensure tip-top conditions in the tank, because ultimately, healthy fish will resist infection without any further help from you.>
PS: Apologies for my English but I'm from Greece.
Thank you in advance,
<Hope this helps, Neale.><<I do concur w/ the guess that the issue here is viral (and untreatable directly). I would look into a larger system, more filtration, and rendering the water a lower pH to improve and preserve the health of these Corydoras. RMF>>

Re: More: re: Corydoras Sterbai issue (Bob, any ideas? Not here, no) 12/8/11
Dear Neale and Bob,
Thank you for your prompt reply! I appreciate your advices but mostly I appreciate your disinterested help.
<You're welcome.>
I will consider purchasing a bigger tank (although my finances do not allow it) but I will keep PH levels in lower levels.
<Ah, now, do not change the pH directly. Although Bob is right, Corydoras do prefer soft, slightly acidic water, you shouldn't have any problems at hardness levels of 20 degrees dH, pH 8. If you can, mixing 50/50 with hard tap water and deionised water (or rainwater) will produce excellent Corydoras conditions, around 10 degrees dH, pH 7.5. Don't add "pH down" products directly. If you do, you're likely to create stressful, unstable conditions.>
Also, if I understood well, I will stop Acriflavine treatment, I will improve their diet with a more varied food and I will get a better filtration system (just to sum up your suggestions). I hope they can make it since (as I see it now), they all have (or will have) the viral issue and not just the one you saw.
<Quite so.>
Once again, I really appreciate your help! I wish I could reciprocate (I'm a web designer if you're interested).
<Be careful what you wish for!>
Best regards,
<Best wishes, Neale.>
Re: Corydoras Sterbai issue 12/8/11

Great tip about the rainwater! I think it's time to use those 5-6 basins I have and collect the rain..! Although I have concerns of the polluted air that is dragged by the drops.
<Quite so. Don't collect rainwater if you live in a dusty, dirty area like a city or somewhere close to a factory. But otherwise, rainwater is generally fairly safe if filtered through carbon and left to stand for a
day or two before use (to allow dissolved CO2 to evaporate off, otherwise the pH will be very low). Cheers, Neale.>
Re: More: re: Corydoras Sterbai issue 12/9/11

Hi Neale,
Thank you for your advice!
<My pleasure.>
Unfortunately, I live in Athens, and it's very polluted here.
<Sad but true, at least as far as dusty air goes'¦>
It seemed that I'd solve the PH issue with the rainwater but I'm not going to risk it with all the exhaust emissions.
<I agree.>
So, what I was thinking to do is make a road trip to a nearby mountain and collect snow instead (it's the only way to avoid any chemicals!) and then follow the procedure you suggested. I hope this will solve my problem but I need to find another way of lowering the PH cause weekly trips to mountains is not ideal unless 2-3 times is enough to stabilize the PH to the desired levels!
<And won't be cost effective either. For now, stick with the tap water. You should be okay. But concentrate on ensuring good environmental conditions. A bigger tank and/or a stronger filter may be a much better use of your money. Corydoras aren't too fussy about water chemistry, and London Tap Water is probably just the same as Athenian Tap Water, yet Corydoras can do extremely well here. Make sure ammonia and nitrite are zero, and do regular water changes to freshen things up. Even tap water will be improved by weekly or twice-weekly water changes.>
Once again, thank you very much for your support.
PS: My offer is still on! So, please don't hesitate.
<Very kind.>
Thank you,
<Best of luck, Neale.>


Corydoras shedding slime coats 8/16/11
Hello, about 2 weeks ago my Girlfriend tried to "help" my community tank by pouring about 10X the dosage of Algaefix which is designed to reduce algae,
<Argh! These products are dangerous, even at the right dose, and should NEVER be used, in my opinion. Even if you magically kill all the algae in a tank, if conditions favour algae, it'll be back in weeks. So the art to removing algae is to change the conditions in the aquarium. Typically this involves adding lots of fast-growing plants under suitably bright light, and then installing a few suitable algae-eating animals (Nerite snails are ideal) that will consume any algae that remains.>
however she managed to kill most of my fish and seriously compromising the health of the others. When I discovered the poisoning most of my fish that were still alive were floating at the top, and my Corys were on their sides. I quickly transferred them all to my goldfish tank, and completely drained my community tank and fixed the problem etc etc. The surviving fish are two long fin black skirted tetras, one diamond tetra and two large leopard Corys. The tetras seem to have returned to normal health.
<Sounds a lucky escape for them!>
However, The Corys went through a few days of touch and go, not eating just sitting there etc. One would swim near the top always gulping air, probably because its lungs were seriously damaged.
<Hmm'¦ no, I'd guess the reverse. If excess slime or chemical irritation was affecting its gills, it'll gulp air and absorb oxygen through its gut. That's what these catfish do. It's normal, and once conditions improve, the Corydoras will gulp air less frequently.>
Now a few weeks later they are doing much better, still not as active before the accident, but are eating and moving around more. However they are still lethargic and also I noticed that their slime coats are starting to fall off.
<Are you sure it's mucous and not skin?>
The water conditions are perfect for them and I recently restocked my Corydoras population, 5 leopard Corys and 1 sterbai Cory and they are all in perfect health in perfect water. The water is at a constant 70-72 degrees, about 30 ppm of General Hardness, and 6-7 PH, no nitrates no nitrites and no ammonia. Will the Corys regain previous health over time,
<If they can, yes.>
or do I have to treat them in some way,
or are they on a slow downward spiral to death?
<Likely not.>
Any help or advice or even information will be greatly appreciated.
Thanks for your time, Jesse
<My gut feeling is your fish will be okay, given time. Cheers, Neale.>


Help with Cory Cat - Upside Down 8/7/11
Hi Crew,
Hoping you can help my Cory cat.
<Will try.>
Here's my set-up: Mature 20 gallon tank. Ammonia 0, Nitrite 0, Nitrate 7ppm Several Cory cats (a few different types), dwarf Gourami, and 6 red phantom tetras (live plants - no new plants or fish in over a year) Temperature has been constant at 77 degrees for a few years
<Very slightly too warm for Corydoras and Red Phantom Tetras, but anything cooler wouldn't be nice for the Gourami.>
One of my cories seems fine in every way - very active, eats well (I alternate between 3 types of sinking pellets for the cories), and social with the others. There is no sign of injury, fungus, redness'¦nothing visible...and no fin clamping. However he loses his balance at times. I first noticed this 4 days ago. I just found him upside down under a plant but not struggling, just resting. I thought he'd passed away and when I circulated the water near him he uprighted himself and went about his business.
<Oh dear.>
When he is swimming quickly is when he loses control, as well as when he is actively eating - he tips, rolls, and most times is able to right himself but not always. I see him still getting enough food to survive at this point.
I've read that fasting, feeding peas, and adding Epsom salts - if so, are Epsom salts safe for cories?
And should I move him to a smaller 8 gallon tank to treat him, or should I leave him in the main tank (or in a 7 x 7 floating breeding trap within the main tank?) to feed him the peas and keep him away from other food?
<A quarantine tank, maintained a few degrees warmer than normal, so about 28 C/82 F, is useful for treating problems with buoyancy. Keep the water level low, 15 cm/6 inches if you can, so the Corydoras can gulp air easily. Feed the peas and high-fibre meaty foods like daphnia and brine shrimp. If constipation is the issue, these will help.>
I'm not sure if a move will stress him more, or if I should be withholding food from the rest of the tank and feeding them all peas?
<It's a toss-up. Keeping Corydoras singly won't make them happy, but there are reasons to treat separately in terms of easier observation, warmer water, Epsom salt, and, if necessary, antibiotics for treating bacterial infections (the other common cause of swim bladder "disease").>
Thank so much to the Crew for helping so many people (and their fish!).
<Thanks for the kind words. Cheers, Neale.>
Re: Help with Cory Cat - Upside Down 8/8/11

Hi Neale,
<Out holidaying in Cornwall>
This is the first time in my fishkeeping history that one of my fish has recovered! Last night my little Cory was in his quarantine tank and was mostly upside down, he was even stuck on the filter once (I ended up wrapping the filter with a tank divider to protect him). The only thing that gave me hope was that I peeked in and saw him poke at a pea once.
I woke up this morning to find him totally normal!! He hasn't turned over once, and you'd never know anything was wrong. He can swim quickly, up and down, and he appears perfect.
<Ah good>
I can't thank you enough for the advice :) I will keep him there a while longer and slowly reduce the temp to get him ready for the big tank if his recovery continues.
Thanks again!
<Will pass on to Neale. Cheers, Bob Fenner>

Injured Corydoras aeneus 3/7/11
I have a question about a Corydoras aeneus (albino) please. I have seven of them, and this May will make three years they have lived with Gymnocorymbus ternetzi, Black Skirt Tetras, in a twenty gallon long tank. Everything has went wonderfully, and I have even raised some of each kind from fry.
I monitor water quality with an API kit and weekly water changes. They have a sand substrate, artificial plants and real floating plants. The Black Skirts do exhibit their pecking order behaviors, but I have only seen this result in a fin shred twice (once all the fins) and both times they healed very quickly without any medication. I have never seen them bother the Corydoras at all, even when they blunder into the Black Skirts and so on. Today one of the largest of the Corydoras has an injury that apparently happened overnight. I looked at the diagnosis chart:
and also the medication chart: http://www.wetwebmedia.com/FWSubWebIndex/fwfishmeds.htm
but I have questions. I thought most bites occur on fins, and in my limited experience, from what I have seen in other people's fish, 'spontaneous' bacterial infections (not from a wound) tend to occur more in the gill / face / pectoral 'armpit' area.
<Is the case. But this is quite clearly a combination bacterial infection and fungal infection; the red is the wound, likely infected with bacteria at this point, and the white fluff is fungus.>
I had a natural looking tank until a few weeks ago when I switched out for some other tacky but fun aquarium décor from an empty tank, and I wonder if he could have got caught in one of the holes in a decorative shipwreck and had to back out.
<Possibly; while fin-nipping might have been the trigger, Corydoras are usually nipped on their dorsal fins first, and there's no sign of that here. The adipose is what's infected here. It's a small fin, and might be damaged by sharp objects. But it's all rather mysterious.>
The shipwreck is easy enough to remove, but removing the Black Skirts would be another matter. I have read on your site that a hospital tank should be as good as the home tank, but I only have a ten gallon available which of course if half the size (I don't know if he needs to go in there or not).
<I would treat in the main tank.>
What do you think is the cause if this injury?
<Very hard to say. The adipose fin is rarely nipped and if the problem was with the substrate, you'd expect to see inflammation of the belly and erosion of the barbels.>
Are the Black Skirts more likely to nip him now with this exposed blood on him?
<Unlikely, but keep an eye on him.>
If his plate is pulled up as it appears to be, is the normal healing for it to fall off, or for it to lay back down again? I have never had to medicate these fish before, so can you tell me the seriousness of this injury? He is moving about on one side of the tank and takes food, etc. I have attached a 79.5 kb photo of the injured fish near the suspect ship, and a 312 kb close-up of the injured area.
Thank you,
<Would treat with a reliable anti-Finrot and anti-Fungus medication, for example eSHa 2000 in Europe or Seachem Paraguard in the US. Cheers, Neale.>

Re: Injured Corydoras aeneus 3/11/11
Dear Neale,
Thank you for your reply. After the pet stores opened up the next day I was surprised to find that they did not have the product you recommended (they are major pet chains after all) but when I came back to check the fish he was dead.
<Oh dear.>
I have ordered some of the medication in case it is needed again. I will look around on WWM and see if there is a list of things everyone should have in their fish medicine cabinet.
<On the whole, no. Apart from medicines having a definite shelf life, a properly maintained aquarium almost never gets sick. Salt is useful for treating the commonest problem, Whitespot, and at a pinch, non-iodised cooking salt works fine for this.>
Since there had not been any more fish added for almost three years (except their babies), and their care is consistent I did
not consider having lots of medicines around. In January I did have a large Black Skirt die (found sucked up by the filter, no signs of any disease or injuries) but since all seven were eating and looking fine the day before and everyone else seemed normal I chalked it up to old age. I took all the new décor out of the tank and put the old back in just in case it caused the injury and death of the Corydoras.
<Hope this is the last fatality for a while! Corydoras should live at around 5 years, and I have some elderly-looking specimens around 6 years old. Cheers, Neale.>

Extremely lethargic Cory, high nitrates 2/21/11
<Hello Angela>
I wrote about a week ago on another issue, and never received a reply.
<?! We respond to all>
I'm hoping I didn't do anything wrong and my message was just overlooked!
<More likely some "computer glitch"... As the WWM "doorkeeper" ala LeGuin's Earthsea double trilogy, I see, post all>
As it is, that issue seems to have resolved itself for the most part. Now I'm dealing with something in my other tank, and I'm hoping for some insight from more experienced hobbyists than myself.
Tank: 14gal (functionally about 11-12gal with substrate and lowered water level), Aqueon filter that came with the "starter kit", temp steady at 75*F, fully cycled and has been set up since early December 2010. The pH runs pretty steady at around 8.
<For what species of Corydoras? This is too high... I'd mix in some water of lower pH... likely RO>
I always treat new water with Prime.
<Likely not necessary, but...>
Residents: 3 peppered Cory cats, 4 albino Cory cats, 2 juvenile mystery snails. The Corys are being quarantined here, their eventual home is a 55gal. I've had them for about 2 weeks.
Tank stats last night, with API test kit:
Ammonia: 0
NitrItes: 0
NitrAtes: over 80 (YIKES!!!)
<Needs to be addressed... Have you read here: http://wetwebmedia.com/FWSubWebIndex/fwnitrates.htm
and the linked files above?>
I performed my usual 30% water change, all I had time for, with plans to do another this morning.
This morning, I tested again:
Ammonia: 0
NitrItes: 0
Nitrates: over 40, close to 80 on test kit
Performed nearly 70% water change. Retested.
NitrAtes: less than 40, but close
<You need to do something in addition to simple dilution for NO3 here>
Now for the main problem: One of the albino Cory cats has been acting lethargic for the last couple of days, is not eating well, and after last night's water change floated belly-up for a few minutes despite all my attempts to match temperature, etc. with the new water. I was afraid we would lose him, but this morning he's better. Not great, since he's still spending most of his time resting on the bottom or swimming *very* slowly a few inches, but he's not floating. Everyone else in the tank, including a new baby balloon molly that hitchhiked home with the Corys, is acting and looking fine. Even the snails, which I thought would be the first indicators of poor water quality.
<Much more likely due to the vagaries of the water changes>
The only thing that changed recently is my husband taking over morning feedings for both tanks for the last week. I think he's been overfeeding this one, because I don't know what else would have caused such a large nitrAte spike in such a short time. There was a lot of "gunk" when I cleaned the tank, which isn't normal. I've taken over feeding again.
<Ah good>
Most of the reading I've done (Google is my friend, yes?) suggests that nitrAtes aren't *that* toxic over the short term, but these levels are pretty high and I've seen people mention again and again that Cory cats are "sensitive" fish. Could the nitrAtes spike alone be the cause of this little guy's problem?
<Mmm, yes>
If so, will continued water changes and much reduced feeding be enough to resolve it? If not, what else would cause an otherwise healthy-seeming fish to be lethargic and go off its food with no other sign of disease? I'm a loss on this one!
<Please read the above citations>
Thank you so much, I appreciate your willingness to help out newbies like myself with your amazing wealth of experience!
--Angela S.--
P.S. Is it just me, or are Cory cats just the funniest/cutest little fish ever?
<Are indeed comical, and faves. I keep them as well>
I was rolling with laughter after their first "feeding frenzy" over a shrimp pellet!! I'd buy a whole swarm of these guys if I could, but hubby says no room for more aquariums...
<Mmm, maybe... Bob Fenner>
Re: Extremely lethargic Cory, high nitrates 2/21/11

Thank you so much for the reply!
<Welcome Angela>
These are albino and peppered Corys (Corydoras aeneus and Corydoras paleatus). The lethargic one is an albino.
<The C. paleatus need much lower pH... the Albinos may be either C. aeneus or paleatus>
I'm in the middle of Kansas, so our water tends to run hard with a higher pH. Even the "expert" at the local store where I purchased these guys admitted it's hard to keep soft/acidic setups here without a LOT of work, <Not so much... easy to mix some tap w/ some RO... Read here:
and the linked files above>
so I stuck with platies for our main fish. I was told that with careful acclimation the Corys would be ok, and honestly the other 6 look perfectly fine. I'll look into the RO water option, but if I can't get the pH down enough, should I find a new home for these fish?
I'm not sure what I'd replace them with. (My 7yo son wanted a school of glass catfish, but there's no way we'd be able to keep them healthy. The Corys were a compromise, since most other catfish types he liked get too big.)
<There are many tools that can/will help you identify fishes, other aquatic life that enjoys your quality water>
I use the Prime instead of whatever brand dechlorinator came with my starter kit because we have copper piping in my house. I wanted to be extra careful to avoid getting copper in my aquariums and killing snails/fish.
<Real good>
The albino Cory is still alive, but he's pretty much the same as yesterday -- not swimming much, resting on a rock most of the time. I haven't seen him eat. I did one more water change last night, being careful to get the rest of the "gunk" out of the gravel. The nitrates are now reading between 10-20ppm, which is where the tank was before its regular water change the previous week. I'm going to be feeding lightly and testing the nitrates daily for the week, I think. I'll also be buying some more plants soon, so that will probably help a bit.
<Will help>
I read as much as I could about Corys/nitrates/etc. on WWM and the 'net in general before I posted, but I probably missed something. I'll go back and check out the links again. Thank you again for the response!
<Certainly welcome. BobF>

Help with treatment plan for Platies/Corydoras 1/12/11
About a month ago Neale and Bob were able to provide me with some help regarding my 40 gallon freshwater tank that houses Platies and Corydoras and set me on a sane path after I panicked and made matters worse.
Originally, I was having issues with my KH rapidly dropping. Attached below is a portion of that correspondence in case it helps with history; however I believe I have sorted that out with switching to RO water and using crushed coral. I have been able to raise the carbonate hardness slowly and currently it is holding at 4
<Degrees KH, presumably, and good for a wide range of tropical fish.>
and my pH at 7.6.
<Also suitable for a very wide range of tropical fish.>
I also was able to get my ammonia and nitrites to zero (they had been spiking).
<Likely as water chemistry stabilised, water quality improved as well, the bacteria being sensitive to water chemistry changes, particularly pH drops.>
If you remember, I had done massive water changes and subjected my fish who had been living in a chronic acidosis state to acute alkalosis then acute acidosis (rapidly dropping pH) and back again. On 12/14 I stopped the massive changes and began the smaller 15-20% daily changes with R/O water buffered to raise the pH slowly. All of my fish had developed fin rot and mouth fungus at this point. I medicated with Tetracycline for 4 days and although I initially lost all my Platy fry under about 1 month old and my remaining Peppered Corydoras, my adult platies, fry over about 1 month old and Albino Corydoras survived and they rot cleared up and they started to heal.
Fast forward to 3 days ago (also current readings):
40 gallon tank
Live plants (multiple all true aquatics)
DH 10
KH 4
pH 7.6
AM 0
Nitrite 0
Nitrate 10
<All sounds fine.>
My Albino Corydoras spawned for the first time in a year or so and the Platies were very active and then I started noticing a problem - one Platy was hiding in a corner. At closer look, she seemed to have some gill damage and damage on top of her head and I attributed this to maybe not being able to recover from previous ammonia damage and the infection that followed the acute shifts in water chemistry. She died yesterday and 2 more adult Platies started hiding in a corner and another is not hiding yet but is not as active. One of the ones hiding has very red gills but the other two have no visible (to me) signs such as damage, gasping, red gills or spots. I thought maybe I hadn't treated them long enough and they still had some type of bacterial infection so yesterday I started Maracyn treatment because it treats for similar infections as the Tetracycline but doesn't turn the water that red color (and is not photosensitive).
<I would agree with you that a stress-related bacterial infection such as Mycobacterium could be responsible. These will create sores and cause infected fish to become lethargic, to breathe heavily, to hide away, and eventually to die. Dead patches of skin commonly appear as white flakes, much like sunburned skin on humans.>
Upon further observation, one other Platy that is very active has white spots flaked on its body. I looked at pictures today and it appears to be Ich. When the original issues with water changes and the fin rot were going on, about 4 of my adult Platies had this similar appearance but it seemed to clear with the antibiotic and I attributed it to being fin rot (this is my first time dealing with either condition).
<Finrot is generally very distinctive, beginning with cloudy patches in the fin tissue and pinkish blobs on the fins, the cloudy patches being dying cells and the pinkish blobs blood vessels congested with bacteria. After a few days the fins erode from the edges inwards, making the fin look ragged, often with the bony rays persisting for longer, the end result being a bit like a cobweb.>
Now through reading, it seems that ICH is only visible for one week and it's possible that they were suffering from both infections and ICH. I'm just not sure. I haven't introduced any new live stock to this tank in well over a year, but as with the bacterial infections, I now somewhat understand ICH is latent in tanks and ready to attack the weak.
<Ich/Whitespot can certainly trigger bacterial infections because the open wounds caused by the bursting white spots as they mature allow "bad" bacteria to get into the fish. On the other hand, stress can allow Whitespot and bacterial infections to become established independently of one another. So figuring out which came first is hard. By the way, there's very little scientific evidence that Whitespot can lie "latent" in tanks because the free-living stages need to find a host within a day or two, at least at tropical temperatures. What *may* happen is that low level infections persist unnoticed for months, and only when something goes wrong do the fish show high enough numbers of cysts to be obvious. Either way, treating proactively will break the cycle. Since the salt/heat method is harmless to fish, shrimps, filter bacteria and plants, this is a no-brainer for me -- treat with salt/heat, if only to cross Whitespot off the list of possibilities.>
These fish have been through HELL over the last month and I'm not exactly sure what I'm dealing with as so much has happened and I'm scared to continue the Maracyn or treat for ICH especially with the Corydoras in the tank. Can you advise the best way forward?
<Mycobacterium infections are essentially incurable, but Finrot and Whitespot should both respond well to prompt treatment. Do read up on these three, and act accordingly.
Thank you,
<Cheers, Neale.>
Re: Help with treatment plan for Platies/Corydoras 1/15/11

Hi Neale. I hope your weekend is treating you well. Thank you for all your assistance.
<Glad to help.>
I've read through the articles and I agree that ruling out Ich is a good idea; however '¦
I increased the temperature to 84 degrees over a day and a half and added the brine mixture (2 teaspoons of aquarium salt per gallon mixed in warm water put in the filtration flow path). I know you state the salinity is trivial for Platies but after adding about half the mixture, my Platies began to show sensitivity (hiding at the bottom and top of the aquarium).
<I doubt the salinity is the issue here. Platies can, do live in brackish water much more salty than this.>
Since they've been subjected to fluctuations in pH and ammonia and nitrite, unstable conditions, recovering from fin rot, could they just be less able to handle any change at this point?
<Seems unlikely. It's important to remember the difference between correlation and causation. Just because one thing follows another, it doesn't mean the first thing caused the second thing. If the Platies were sick or stressed already, then they might have gotten worse whether you added salt or not. Just make sure you're adding the right amount of salt, and that you're doing it in the right way. I'd turn the heat down a bit -- Platies come from quite cool habitats, and I'd not warm them above 28 C/82 F.>
The dilemma I face is that although they don't seem to like the salt, the one Platy who was hiding originally, came out today to swim for the first time in days today which is encouraging. While the other Platy with white spots has lost several of the bigger spots but is more lethargic which is encouraging and not so encouraging. My ammonia and nitrites are rising yet again (it seems the good bacteria doesn't like the changes either). The last dose of Maracyn was last night so I can up the water changes to reduce these levels more. I'm hoping without the strain of medicine and better control of ammonia and nitrites levels, the Platies will handle the current salinity better. I just want to make sure that my decision to not reduce the salinity is a good idea considering the Platies are showing sensitivity to it. I feel like we're (the fish and I) are damned if I do and damned if I don't at this point. I don't know which is the lesser of two evils.
<Would use the salt/heat method regardless.>
All but two fish are showing interest in food, the original sick one and another that I believe is severely constipated. I know I shouldn't be feeding them per the ammonia and nitrite, but I was trying to get the constipated one to eat a pea.
Also, in my reading of Ich, I've learned it can transmit on anything wet but I couldn't find instructions on how to handle transferring new plants into a tank per this possibility?
<Treat plants as potential sources of Whitespot. Quarantine any plants taken from tanks with fish in it, or for that matter from tanks likely to be on the same water circulation system in the pet store. Plants bought online from aquarium plant growers should be safe though.>
<Cheers, Neale.>
Re: Help with treatment plan for Platies/Corydoras 1/15/11
Okay, great. I've turned the heater down to 82 F. I didn't think the plant quarantine all the way through. I was thinking that you would never be able to tell if the plant had Ich on it but if quarantined, there wouldn't be a fish host to continue the cycle.
Once again - thank you.
<Yes, if the free-living parasites are unable to find a host within a period of time, they die. At tropical temperatures, that's about 24-48 hours. At room temperature, it may be several days longer. But I'd isolate plants for 7 days, at least, to be fairly sure they weren't carrying Whitespot parasites.
Cheers, Neale.>

Cory catfish with skin peel (RMF, Costia?)<<Maybe, or just water quality>> 1/23/11
I have looked over the site for two days now and commend you on how well you cover everything.
I saw one post addressing this issue while I was searching, but most of the similar posts deal with other fish and not Corys. In the meantime, I lost two yesterday and another one tonight. I had a dozen, several of them regular breeders, and I am afraid I am going to lose more. Tonight I see two more with the beginnings of this strange "disease."
<I see.>
I have a 55 gal freshwater tank, a community of mostly tetras, Danios, and Corys. Ammonia is 0; nitrites 0; nitrates 160; ph 7.0; temp 72*. General hardness 180 and Carbonate hardness 0. <<I doubt this>>
<All sounds fine.>
I usually test with both test strips and chemicals in "test tubes" of tank water. About a month ago, I took the tank down about 1/3rd, cleaning the filter, siphoning debris from the gravel, etc. I waited and then
introduced some new tetras, Danios, and plants to the tank - would have been a few weeks ago. Threw about a pinch or two of aquarium salt in the tank. (Why? I don't know. It's the first time I've ever done that.)
<Indeed. Salt is much overrated and misunderstood.>
I have had fish for over 50 years (!) and have never seen my Corys get sick and die like they are now. I need your help!
I have attached two photos for you to see. This "disease" begins as a small spot of white (not cottony and not like Ick) then begins to spread like a blotch. It looks like the skin has died; it has turned white and
appears to be peeling like a sunburn would. I added a fungus treatment last night (Jungle "Fungus Clear" with Nitrofurazone, Furazolidone, and potassium dichromate). This afternoon, I took the tank down about 8 gallons, refilled with treated water (I use API "Stress Coat"), and added a large circular air stone. Everyone looked chipper and the Corys were swimming and playing, but a short while ago my "big mama" (the one in the photos) gave up and died. Please help me and my Cory "kittens".
<I think this is Slime Disease, also known as Costia. It's quite tricky to fix, but you should be able to find a medication sold in your area that works. Do note that while Formalin works, it's quite toxic to catfish (as
well as most other fish, to some degree or another) so isn't recommended. Raising the temperature to 30 degrees C can stress, even kill, Slime Disease, but this can also stress your fish, so be careful if you choose to use this method.>
Thank you so much! Anna
<Cheers, Neale.>

Re: Cory catfish with skin peel (RMF, Costia?) 1/23/11
Thank you so very much! Being Sunday here, we are out a bit today, but will stop at the pet store on the way home and see what we can get. The young man I spoke with yesterday at PetSmart has several large community tanks, and he didn't think it was fungal either. Man, I was hitting every resource I could think of during the past two days. As I said, yours was the best - I just didn't see this covered in a way I could readily apply it to my situation. Thank you so much for your quick answer!
<Glad to help.>
As there is Fungus Clear in there now, do I need to take the tank down by half or anything?
<Would do a water change, a good 30% or so, but otherwise there's no need to do anything special.>
I went back on your website and read a few articles about Costia (now that I know what I'm dealing with), and saw an article penned by Neale Monks.
Is that, perchance, you?
<Yes, indeed.>
Awesome!! (Not that it makes a difference to the discussion at-hand, but I am a Scot-Irish American - Clan Cameron.)
<Interesting to know.>
<Good luck, Neale.>

Re: Cory catfish with skin peel 1/24/11
Thanks again, dear Dr.! I stopped at PetSmart, got "Triple Sulfate"
(sodium sulfathiazole, sodium sulfamethazine, and sodium sulfacetamide). I mentioned to the lovely lady there that the Corys are vulnerable to salt (sodium.) Being that there is no caution note on the container, this is what she recommended. What do you think? Safe to use?
<Hello Anna. Corydoras aren't vulnerable to sodium as such, but to sodium chloride if the salt concentration is too high -- though contrary to what inexperienced fishkeepers believe, they aren't "allergic" to low salt concentrations such as those used to treat Whitespot. In fact the salt/heat method treats Whitespot on Corydoras safely and effectively. In any case, the product you bought should be safe to use because the sodium compounds are not sodium chloride and won't affect salinity. Cheers, Neale.>
Re: Cory catfish with skin peel 1/24/11
<PS. Do see Bob's comment on the Daily FAQs that water quality may be an issue, and worth reviewing. Excess mucous production can occur when Corydoras are stressed by their environment. The fact you reported zero carbonate hardness is surprising, and as Bob noted, unlikely; or if you really do have zero carbonate hardness, perhaps by using water from a domestic water softener, the resulting water is unhealthy and likely to experience very rapid pH changes (drops into the acidic range, usually) between water changes. Review this aspect too. Cheers, Neale.>
Re: Cory catfish with skin peel 1/24/11

Thank you so very much for this and the other note! I will go look at Bob's comments on the FAQs - but will have to do it on my lunch break as I am headed off to work this morning. I do not have a domestic water softener, and was using a test strip. hope that it was accurate, but I'll check that again this morning.
<Okeley dokely.>
I'll start the treatment on the aquarium this morning before I go. The package indicates 4 treatments with a 25% water change in between, an expensive treatment of about $30 so I sure hope it takes care of the problem.
<Yowsers! But as we point out repeatedly here, prevention is better than cure. Find fish suitable for your water chemistry, water temperature, and experience level. Kept right, fish rarely get sick.>
Worth it, though, if I don't lose any more Corys. Again, thank you so much!
<Glad to help. Cheers, Neale.>

Cory playing dead 11/5/10
Hi Crew,
Thanks for all the great work you do. I'm hoping you can help me again.
One of my four albino Corys has been behaving very oddly over the past few days.
He eats normally with the others each morning and swims around a bit but then spends much of the rest of the day lying on his back, appearing to be dead, until he is poked or touched by something. The first time I saw this I thought he was dead but when I went to net him out of the tank he immediately jumped up and started swimming around normally.
Each day since then I have noticed him doing the same thing but as soon as I put the net near him he rights himself and swims away. I saw him do the same thing when he was nudged slightly by another fish.
Is he really sick or is there some other explanation for this weird behaviour? The other three are behaving perfectly normally.
Thanks very much
<Mmm, well, Corydoras can be/act like real clowns at times, but laying on their back or sides is not normal, healthy behavior. I'd look about for an anomaly water quality wise, or at least act proactively and institute a series of daily partial water changes and gravel vacuuming. Bob Fenner>

Cory with hole in the head? (Bob, anything to add re: Red Blotch Disease)<<Nothing further>> - 10/12/10
Dear WWM,
I have a Corydoras julii with a hole in the head! It started out looking like a small scrape just above the mouth, but in the past week has eaten away at the flesh until I can see part of the "nose" bone. I also just
noticed a similar spot behind the left pectoral fin. These spots are flesh colored, with nothing in or on them from what I can see. The fish is breathing rapidly with pink gills, but otherwise eating and swimming fine,
although has slowed down a bit. The other fish are not affected by this.
This fish is in a mature (cycled since March) 10-gallon aquarium with four neon tetras, one black neon tetra, and a Bristlenose Pleco. I have had the Cory for a few months now. The water conditions are as follows:
Temp: 78 degrees, although with cooler weather it goes down a few degrees at night.
<Good; ideal water temperatures for most Corydoras are between 22-24 C/72-75 F. Keeping them much warmer than this will shorten their lifespan.>
pH: 7.8
KH: 120-180
Chlorine: 0
GH: 150
Nitrite: 0
Nitrate: 5-10
Ammonia I have not checked in a few weeks, but assume it is zero.
I have been very sick the past couple of months and have not been able to clean the tank properly, although I have more than adequate filtration (Whisper Power 20 and Aqua Clean 20 powerhead with undergravel filter).
I combed this site looking for answers and I didn't see any (not to say that they aren't there, but that I may have missed them.) I did find some helpful information such as proper diet for Corys and that they are social fish, so kept by themselves they may be stressed. I will remedy these as soon as I am able, but my main questions are 1) what is this? and 2) can I treat it? I have had this problem with Corys in the past and have just euthanized them because they're only a couple bucks and I was using them for "maintenance fish", not very attached to them - although I do like them.
Thank you for any help you can give me! Vanessa
<Hello Vanessa. It's unlikely your fish has Hole-in-the-Head. For whatever reason, this isn't usually a problem with "primitive" fish such as catfish or carp. My guess would be you're dealing with a bacterial infection. Some are opportunistic. A common problem with Corydoras is to keep them in tanks with gravel. While gravel isn't in itself dangerous, it does trap dirt and in the process cultivates bacteria. Should the gravel also be abrasive, there's a double whammy there because the abrasions on the belly, fins and especially the whiskers become open wounds, and bacterial invade these and cause infection. Healthy Corydoras should have quite long whiskers: I've got some Peppered Corydoras in a tank with sand, and the bigger specimens around 5 cm/2 inches long have whiskers a good 1 cm/0.4 inches long, and distinctly tapered at the ends. Corydoras kept in tanks with gravel commonly have abraded whiskers that are much shorter, barely a few millimetres beyond the mouth, and the whiskers have blunt ends as well. If your Corydoras have whiskers like that it means the substrate is dirty and/or sharp, and either way, possibly both, your Corydoras are being subjected to low level bacterial infections. This isn't fatal, and many
Corydoras are kept this way and live for years. But it is a sign that conditions aren't 100% perfect so far as Corydoras are concerned. Cleaning gravel regularly helps a lot, and that usually means using a gravel vacuum.
Reverse-flow undergravel filtration will also help. But it should go without saying that smooth, lime-free sand is infinitely better for Corydoras than gravel, and no-one who keeps them in sandy tanks would dream of switching them back to gravel! Among other things, sand is kept clean by the catfish themselves, so bacterial infections are far less common. Now, the second possibility is the infamous Red Blotch Disease. This is a systemic bacterial infection that is usually caused by poor shipping but can come about through unhealthy aquarium conditions. A broad-spectrum antibiotic may help, together with, curiously enough, a teaspoon or two tonic salt per gallon, the salt in itself not being a cure but somehow reducing stress on the fish during the antibiotic therapy. Red Blotch Disease is less common today than it once was, aquarists largely understanding what it is Corydoras need to do well. But because you have had this problem before, my guess is that you are doing something wrong in the way you're keeping these fish, which is why you keep "failing" to keep Corydoras spp alive for long. Review the needs of these fish, and act accordingly. One last thing, should you need to destroy affected fish, be sure to review humane methods of doing so; some of the old school approaches, like laying fish on crushed ice, are now recognised to be neither fast nor painless.
Cheers, Neale.>

Corys Dying 9/26/10
Hello Crew, hope all is going well for you there. I have a question, please. I have a 75 gallon fw aquarium with 2 female gold gouramis and 6 assorted angel fish. I have had these for quite a while in addition to about 10 Cory cats. Over a period of time some of the Corys have died off so I went a couple of days ago to purchase 4 green Corys which were bigger than the other assorted ones I already had in the tank. After I got them home and acclimated them they all seemed to be doing well and swimming around the tank. Then over the next 2 days when I woke up and looked in my tank all of my Corys were dead. Some looked chewed up and some had their tails bitten off (at least it looked that way). Also I am missing a small angel fish which I cannot find anywhere. I don't know if that is related in any way but I would like your opinion on what might have happened please. Thank you,
<Hello James. Do understand most Corydoras prefer quite cool water, 24 C/75 F being the tops for most species, and if kept substantially above that they will not do well. The exception is Corydoras sterbai, which is fine up to 28 C/82 F. Corydoras are also obligate air-breathers, and they need to be able to swim to the top of the tank easily. If the tank is much deeper than, say, 45 cm/18 inches, they may find it difficult to do this. A lot depends on the size of the Corydoras, water current strength, resting places between the substrate and the surface, and how aggressive the midwater fish are. But it may be a factor. Thirdly, Corydoras depend upon the bottom layer of water being of good quality. Make sure the filter is
working properly, and that there's a good, strong current along the bottom of the tank. Canister filters and undergravel filters generally provide this without problems, but hang-on-the-back filters might not if the inlet pipe does go right down to the bottom of the tank. Adding an airstone or two at the bottom of the tank will help significantly by creating an upwelling flow of water that draws bottom water to the top of the tank, and this in turn means surface water will be pulled down to the bottom.
Naturally, check water quality and water chemistry more generally.
Corydoras need 0 ammonia and 0 nitrite. They aren't fussy about water chemistry, but it should at least be stable, so pH changes should be minimal. Something in the range 3-15 degrees dH, pH 6.0-8.0 is fine.
Finally, Corydoras may be stressed by copper and formalin based medications used to treat Whitespot and the like. Because you've also lost an Angelfish, I'd be tempted to focus on water quality above all others, and check the filter is properly configured, stuffed with the right sort of media, properly maintained, and adequate to the numbers of fish being kept.
I'd review water change frequency, tending towards more, small water changes rather than big, infrequent ones. If you can change 10% every 3-4 days, that'd be ideal, at least for a month to see if things settle down.
Review the amount of food being given, and check the Corydoras are getting enough to eat, e.g., by offering 1-2 algae wafers every couple of nights.
Cheers, Neale.>
Re: Corys Dying 9/27/10

Thank you.
<Happy to help. Cheers, Neale.>

Quick question about Corydoras catfish 5/11/10
<Hello Judy,>
I was just wondering if it is harmful to keep just one Corydoras catfish?
<"Harmful" is a difficult word to use here. Yes, these are schooling catfish, and if kept singly the loner will be stressed and therefore more likely to get sick.>
I have a 10 gallon tank with 6 Neons and one Corydoras. Is one alone stressed out since they are so social??
<Yes. Get four more of the same species!>
Thank you!
<Cheers, Neale.>

Corydoras paleatus, fat behavior 5/5/10
I have 5 Corydoras paleatus in a 160 litre aquarium with the temperature at 22C.
<Very good.>
They've all lived in this aquarium for over a year and spawn regularly.
<As is their wont, when happy.>
The ammonia and nitrite are both 0 ppm, the nitrate is 10 -- 20 ppm and the pH is 7.2.
I change about 30 -- 40 % of the water per week. This morning I have noticed one of the females is acting a little strange. The best way I can think to describe it, is she is looking a little 'floaty' in that she's not resting on the bottom or looking for food but is instead floating just above the substrate.
<Yes. Does happen. Sometimes means she's swallowed too much air, but could also be simple indigestion or constipation.>
She is also going to the surface for air a lot more than usual but when she returns to the bottom this air seems to be being expelled quickly from what looks like her anus, meaning a couple of minutes later she returns to the surface for more air and the process repeats itself.
<I see.>
I can't find any information on the web about whether or not this is a problem, perhaps because I'm not sure what I'm looking for.
<To try raising the water temperature a bit for a few days, to 25 degrees C, and see if that helps. You could also add a little Epsom salt to the water, 1-3 teaspoons per 20 litres, as this has a mild muscle relaxing action that works like a laxative. It won't stress the fish at all, but if they have blockages of one sort or another, it can help.>
One of the other females is looking particularly fat this morning and I think they are ready to spawn again.
<May well be.>
Could this strange behaviour be anything to do with spawning or should I be worried?
<Wouldn't be unduly worried. Observe, act as mentioned above, and only worry if she doesn't improve within a few days.>
I am concerned something is causing pressure inside her which is causing the air to be expelled so quickly.
<Possibly, but I can't think what.>
I hope I have provided enough information for you to be able to give advice, if there is anything else I need to provide, I'd be happy to.
<Good luck, Neale.>

Sick Cory cat 3/25/10
I have a question about a sick Peppered Cory cat I have. This morning (after a water change last night) I noticed a large white spot on the back of his head and I'm not sure what it is. I was unable to find anything like it in the archives. He is in a 20gal tank with one other peppered and a skunk, along with 20 Frontosa fry. They measure inch or less. I am waiting for my 72 bow to cycle before I put the Frontosas in there. The tank has been set up for 2 months now, the water is clear and I do 25% or more water changes every Wednesday and on the weekends. I don't have any equipment to test the water to get the exact numbers but I know its pretty good. Do you have any
ideas as to what it might be? Is it possible that I bumped him with the cleaning hose and that would cause a white spot? Please advise
<Hello Paul. Without a photo, it's difficult to be sure. Do start reading here:
This page has a dichotomous key that helps to separate the most common problems. Tiny white spots can be Velvet or Ick, while white patches may be Finrot or the start of a fungal infection. Damaged skin is often white, and
heals by itself under good conditions, but excessive patches of mucous, which tend to be off-white to grey rather than bright white, imply a reaction to poor environmental conditions or certain parasites including Costia ["slime disease"]. Be open minded; you idea of "good" conditions may not be what I consider good, or for that matter what Finrot bacteria and happy catfish consider good! Cheers, Neale.>

Sick Cory Cat - Please Help 1/21/10
Hi Crew,
Sure hope you can offer some suggestions. I have a sick Cory cat and am not sure what to do.
<Will try my best.>
20 gallon planted community tank: 0 Ammonia; 0 Nitrites; Found last week my Nitrates went to 35 (!), down to 20 now and I'm working on that (my tank is typically at less than 10..
<In itself, nitrates of 35 mg/l aren't likely to cause sickness. Indeed, the tap water in many parts of England has 50 mg/l nitrate! Cichlids and certain other fish are very sensitive to nitrate, but catfish on the whole are not.>
I think excess shrimp pellets had caused this spike as Nitrates).
Temp 77,
<Far too warm for most Corydoras. Almost all species -- the notable exception is Corydoras sterbai -- prefer (need) quite cool water, about 22-24 C (72-75 F). The warmer you keep them, the less healthy they will be.
Obviously you need to choose tankmates that also like fairly cool water; Platies, Neons, Danios etc are all ideal.>
Weekly water change/vacuum.
Fish include 1 swordtail, 1 Farlowella, 5 tetras, 1 powder blue Gourami, 5 little Otos, and several Corys of a few different species.
<Again, another stress issue is social requirements. Note that you should keep at least five specimens of each Corydoras species. Having five specimens of five species won't make them feel particularly happy, and an unhappy fish is a stressed fish, and a stressed fish can easily become a sick fish.>
PH around 7.0, and the water is hard, but I have had Corys for a few years and have never had a problem (I believe they like softer water?).
<Actually doesn't matter much.>
Nothing new in the tank in recent months
Not sure what species this sick Cory cat is...he looks similar to a black fin Cory, though not identical. He is the smallest in his group of four, and I've had all four for a year and all have been very well.
Not eating for at least 4 days, no interest in meal time
Isolated from others at times, but not hiding
Sleeps on leaf in the middle of the tank
Goes to the surface more frequently than normal for air, then swims back down
Clamped fin
Barbells look much shorter than usual but I will check on that again tonight with a flashlight
<Erosion of the barbels is a classic sign of secondary bacterial infection.
In short, a dirty or abrasive substrate damages the barbels, and bacteria set in. It's essentially Finrot. Corydoras do best in tanks with [a] smooth silica sand substrate; and [b] strong water flow along the bottom of the tank. Departures from these two criteria increase the risk of barbel erosion. The classic causes are gravel rather than sand; sharp sand (e.g., Tahitian Moon Sand) instead of smooth sand; and a filter that doesn't have much water flow along the bottom.>
* He is turning a very dark colour, not quite black but close to it. This is what first alerted me to a problem, over a week ago. This colouration is uniform throughout his entire body. No signs of any fungus, and swimming is still strong All other fish are doing very well
I know Corys like low nitrates so I did a 20% water change on Sunday, and have since done two 5-10% water changes, in case the nitrates at 20 are making him sick.
I am wondering if I move him to a 10 gallon hospital tank, with a fresh vacuum and water change, will that cause too much stress being in there alone?
<Yes, is very stressful.>
Or would he have a better chance of recovery staying where he is (perhaps with a larger water change?). And if his barbells are disappearing, are they gone for good?
<No, will grow back.>
Really not sure what to do and am open to all suggestions. Thanks in advance for the help, and for this amazing web site!
<Do review the needs of Corydoras, and act accordingly. If you suspect Finrot, treat as per Finrot, but take care to avoid copper or formalin, as these can be highly toxic to catfish generally. Cheers, Neale.>
Re: Sick Cory Cat - Please Help <ADDITIONAL INFO>
Hi again,
I checked in on the little Cory in better light, and definitely his barbels are nowhere near the length of the other Corys of the same species. They are either very short or gone. Is there any hope for him?
He is more listless tonight that he was yesterday.
<Check/improve water quality; treat as per Finrot, avoiding copper and formalin based medications if possible.>
No fungus or anything present around his mouth.
I also did another 10% water change tonight and nitrates are still around 20 (out of the tap they are close to zero).
<Do read previous e-mail. Cheers, Neale.>
Re: Sick Cory Cat - Please Help
Hi Neale,
You've been most helpful, as always. I learn so much from you and the crew.
<Glad to help.>
Most reading I've done on Cory cats says 72 - 79 is ideal, so I didn't realize that 77 was too warm.
<Depends on the species. Many general web sites will give this sort of range based on no particularly deep knowledge of these catfish. But if you read books on catfish, or visit sites like Fishbase or Planet Catfish, a different conclusion will be reached. By far the vast majority of Corydoras come from relatively shallow water where temperatures vary but are often cool. Some species, including Peppered Corydoras and Bronze Corydoras, actually like fairly brisk conditions, down to about 18 C in winter (68 F).
The infamous Bearded Corydoras (technically, Scleromystax barbatus) wants things even colder, around 15-18 C (about 59 to 68 F), all year around.
Most of the other species are happy at middling temperatures, around 22-24 C, but above 24 C (75 F) your list of happy Corydoras gets very short.
Essentially just the one species in terms of what's available, Corydoras sterbai. This hothouse flower has become known as the "Discus Corydoras" simply because it's the only one happy at the 28 C (82 F) that Discus, Angelfish and other warm water tropicals need.>
I will definitely start to slowly reduce the temp of the tank by a few degrees, over time. Thanks for that info.
<Make sure your other fish will be happy.>
Regarding treatment for fin rot, is there anything you suggest (I'm in Canada) that will not harm my Farlowella? I also have been graced with a 1/2" "surprise" pond snail and am hoping none of these critters will be harmed if I am treating my main tank for fin rot.
<I have no idea what's on sale in Canada, I'm afraid. Here in England, the product I rely on for Finrot is called eSHa 2000, and I've always found it safe around delicate fish such as catfish and puffers. Provided you avoid copper and formalin/formaldehyde (look on the ingredients list) you should be okay.>
You also mentioned strong water flow along the bottom...would it benefit this tank to add a bubble wall at the bottom? I have one that I keep in my 10 gallon (currently empty).
<Sure. Worth a shot.>
Thanks again, Neale!
<Cheers, Neale.>
Re: Sick Cory Cat - Please Help
Thanks for the education, Neale! I will expand my reading. Much appreciated!
<Always glad to help. Cheers, Neale.>

Leopard Cory missing an eye 1/9/10
Tonight about an hour after I fed my fish I noticed that one of my leopard Cory's missing an eye. Tank mates include other leopard Cory's, Kuhli loaches brilliant Rasboras and a Opaline Gourami and a black ghost (he is about 4-5 inches. Just taking a wild guess that the only fish that might of gone after him would be the BGK?
<Is the most likely suspect, yes>
My other possibility guess is that the Cory may have gotten in the BGK's way and got knocked into each other. It seems that from reading other posts on here that ... in general.... BGK's don't go after Cory's????
<Not generally. The loss of the eye may be attributable to a physical injury... the Corydoras "bumping" into something sharp... This fish can still live a good life w/o the one eye>
Anyway I don't know if I did the right thing but I took the Cory out of the tank and put him in a big bowl for the night. If he makes it through the night should I put him back into the tank?
<I would return this fish to the main tank pronto/right away>
Or if I do will his missing eye injury get infected and affect the rest of the tank?
<It will not>
Whatever advice you can give will be much appreciated.
Thank You
<Welcome Joe, Bob Fenner>

Re: Vacation question. Corydoras hlth. 12/23/2009
Thank you for the quick response. After receiving your email I noticed another issue with one of my Corydoras. There is a small white spot at the rear of the dorsal fin near the body. I tested the water and nothing has changed in terms of quality that was reported in my last email. The tank is 78 degrees.
<Much too warm for most Corydoras; with the exception of C. sterbai, most of the traded Corydoras are happier (i.e., healthier) kept between 18 and 24 C (68 to 75 F) depending on the species. Corydoras paleatus and Corydoras aeneus for example like the cooler end of this range. Many hobbyists keep them much too warm, as they often keep Neons, Danios, Rosy Barbs, Platies, Swordtails and many other tropical fish much too warm.
Choose fish that enjoy the same temperature range, and keep them at an optimal temperature.>
Having nothing new added to the tank in about 4 months I am hoping if you can tell me if this is Ick or something else.
<"Something else". This is a tumour of some sort, likely benign, or else the catfish equivalent of Fish Pox (which carp get) or Lymphocystis (which is mostly found in Perciform fish like cichlids). In and of itself, not life threatening, but a good indication the fish's immune system has been weakened by chronic exposure to the wrong (or poor) conditions. In the case of Corydoras, lack of water circulation at the bottom of the tank, as well as a substrate that isn't routinely cleaned, are both examples of sources of stress. Whether a tumour or a viral infection, no cure as such, simply time, a balanced (vitamin rich) diet, and good water quality.>
none of the other fish have any noticeable spots. I had to take the pictures from above as the Corys never seem to stop moving in the tank in their never ending search for anything edible.
<Please do observe our "house rules" re: images -- to avoid filling our 10 MB e-mail inbox allowance, keep individual images to 500 KB or less... yours were 5 MB! If someone else did this on the same day, other folks
would have their messages bounced back.>
Thanks again,
<Cheers, Neale.>
RE: Vacation question.
Thank you again I will try to drop the temp a few degrees.
<Do check the other fish don't mind. As I mentioned, many fish like relatively cool conditions. But other fish, notably Ram Cichlids Cardinals, Mollies and Angelfish, will object strongly to being kept cooler than they prefer.>
I vacuum the gravel once a week and have good circulation down at the bottom.
Have a wonderful holiday.
<I intend to! Enjoys yours. Cheers, Neale.>
Re: Vacation question.
Oh and sorry about the large file size
<No problems. Just remember for next time! Cheers, Neale.>

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