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FAQs on the Cardinal Tetras 

Related Articles: Cardinal Tetras; A School of Beauty, Part II,  by Alesia Benedict, Neons, Cardinals & Their Kin; Selection, Maintenance & Healthcare by Neale Monks Characid Fishes

Related FAQs:   Neon Tetras, Characid/Tetra Fishes,

Cardinal tetra with balloon like scales       10/8/19
Dear WWM,
My cardinal developed a single, large, solid white, ball-like spot on its flank about 2 weeks ago. It seemed completely active and normal otherwise and the single spot was unlike anything I could find pictures or descriptions of. After speaking to the fish store who didn't think it looked fungal, I decided to watch and wait. The "spot" disappeared after 7 or 8 days. At this point the fish developed some fluffy cotton wool like patches which seemed more classically fungal, and another in the shoal of 8 cardinals also seemed to show a small patch of something similar. I put the two fish in a hospital tank and started to treat with a treatment called Dessamoor, which contains copper sulphate, ethacridine lactate, Methylene blue, and Acriflavine chloride. I followed the dosing instructions accurately but when I checked in on the fish after about 4 or 5 hours (who had seemed pretty normal behaviourally despite the cotton wool), they had lost most of their colour. I guessed that if I left them there they would die. So I put them back in my community aquarium and just watched. Over the next week, the fish with the more obvious problems seemed to get more of the growth. The other one's possible cotton wool tuft seemed to clear up. Then I realised about two days ago that the scales of cardinal with the greater problems seemed to have swollen up hideously - see picture attached. I'm not sure when this started - it's possible that the 'cotton wool' appearance was an early stage of the process. It was a bit difficult to see well in a well planted 120 L tank.
I have now put this poor fish in a separate container (my "hospital" tank is currently occupied by an aggressive dwarf gourami). I will buy a new hospital tank for the cardinal tomorrow. I wanted to try salt but I've read that cardinals tolerate it poorly. I have just bought Melafix and Pimafix and was going to try these empirically - but having read other advice on your website it seems these don't do anything. So I am at a loss. I have no idea what to do or what the disease is. Oddly, the fish is active and until I separated it was behaving as normal and eating well. Now it's stressed, buzzing intermittently about its container, and won't eat, but I am pretty sure the latter is stress-related rather than due to the illness. The 7 other cardinals all look fine, as do 3 corys and an Ancistrus. I've a couple of dwarf gouramis as well. They occasionally seem to get agitated and brush against plants as if they are itching these past 3 or 4 days. But they have no external stigmata thus far, and most of the time look and behave normally and seem happy enough.
Finally, the problems seemed to start when over a 2-month period I cleaned the tank about 2 times only given holidays etc. Usually I do a partial water change (approx 30%) weekly. After separating the cardinal a couple of days back, in the absence of knowing what if anything to treat the main tank with I did a 70% water change and rinsed all the plants, driftwood, gravel. My water parameters are nitrite 0, nitrate 25 mg/L, general hardness >16°, carbonate hardness 20°, pH 6.8, Cl2 0.
Please help...!
<I am not optimistic here. The bubbles are epidermal tissue that has swollen up with tissue fluid, and now protrudes past the scales. It's the sort of thing we'd call Dropsy if the swelling was internal. There's no obvious solution here. A good antibiotic might be worth a shot. The use of salt, at 2 gram/litre, is perfectly safe with Amazonian fish such as Cardinals for short periods (a few days or weeks) and is actually much less stressful than traditional medicines such as formalin and organic dyes. It's a tough one. If this fish is stressed, then humanely destroying it will be the best move. But if it's feeding and otherwise behaving normally, you might elect to medicate. Good luck, Neale.>

Issues With High pH, Suitable for Cardinals?         4/16/19
Dear WetWebMedia,
Thanks for your advice from a couple of weeks ago. I have completed cycling my tank but am currently having some further issues with my tank's pH. I would appreciate your advice.
<Sure thing.>
I won't repeat all the details of my tank/water here but I guess the pertinent info is as follows:
Tap water:
Total Ca/Mg: about 20 dGH
<A bit too high for Cardinals.>
Alkalinity: 216mg/l = 9.9 dKH
<Also too high.>
pH: about 7.3-7.8 after standing/aeration. I have noticed the tap pH has increased in the last couple of days, perhaps the water company is adding something to the water.
<Possibly. Best ask them.>
RO water:
No detectable hardness on my test kit.
pH similar to the tap water.
<Should be around 7; ideally exactly 7 if the RO filter is working properly.>
Tank water:
Total Ca/Mg: about 7 dGH
Alkalinity: 108mg/l = 5 dKH
pH: 7.8-8.0 in the morning and up to 8.2-8.5 in the evening before the lights dim.
<Interesting the pH goes up, but that can happen if there is a lot of photosynthesis going on. Plants remove dissolved carbon dioxide during photosynthesis, and since dissolved CO2 is carbonic acid, removing CO2 causes the pH to rise. Furthermore, some plants, such as Elodea and Vallisneria, can absorb carbonate and bicarbonate ions from the water, and use these as a carbon source for photosynthesis. It's called 'biogenic decalcification' and can cause the pH to drop as well. You know plants are doing this in some cases because crystals of white minerals (a bit like limescale) appear on the leaves.>
The tank is fully cycled but uninhabited. It does however contain a few Cryptocorynes and a bundle of something that I think is Elodea that I have left to float on the surface. These have been in the tank for a week and a half and the Elodea in particular has taken off - some of the roots that have grown from the stems have grown so fast that they have actually reached the substrate and anchored themselves!
<Elodea is a classic "hard water" plant. It often does badly in soft and acidic conditions. So if it thriving, chances are your water is (at least) moderately hard and alkaline.>
I was aware it is a fast grower but it is astounding to see how vigorous it is in reality!
<Indeed! Fast-growing plants can need to be cropped every week if they are doing really well.>
The issue I am having is the elevated pH, despite using 50/50 RO/tap water as you suggested. I had initially set the alkalinity to 9dKH with additional baking soda but when I noticed the high pH I stopped this and have now only used the RO/tap mix for water changes. This has not lowered the pH although as expected the alkalinity is half that of the tap water.
As you may remember, I had planned to keep cardinal tetras (captive bred) so I had the LFS test their system water. They report Ca/Mg at 5 dGH and alkalinity at 5 dGH, but their pH is 6.9-7.2 despite their using a 50/50 RO/tap mix as well. Our tap water is unlikely to be much different as the distance separating us is less than 5mi so I am unsure why there should be such a large difference.
<See above re: photosynthesis. The use of a pH-controlled, automated carbon dioxide fertilisation system can help here. But that's expensive and fiddly to use.>
I can only think it is because either the LFS system contains a large amount of organic acids due to their bioload (they don't use peat); there is something in my water produced by the plants/algae/bogwood that is alkaline in nature; or my plants deplete the CO2 in my tank water faster than it replenishes at night (or all three).
<Ah; would bet on the third explanation.>
In any case, I am not sure what to do now.
<Well, one approach would be avoid using plants that grow too rapidly, particularly those capable of remove carbonate and bicarbonate from the system. So reduce the amount of Elodea, and Vallisneria if you use them. Of course removing plants means algae can take over, so I'd suggest at least some floating plants that use CO2 from the air but minerals from the water.
These suppress algae quite effectively. Failing that, plants that are less adapted to high hardness conditions, such as Hygrophila, might work better.>
I am not keen to forcibly adjust the pH with acid or buffer and I also want to avoid a CO2 system because it is a lot of work and I don't think I am ready for that.
I guess peat filtration might be an option but I am also reluctant to do this as I understand this is hard to control, will deplete the alkalinity, and the water staining may impact my plant growth. Do you have any other suggestions for lowering the pH, or should I just leave it alone and focus on keeping the alkalinity stable?
<As the tank stands now, pH is cycling in quite a normal way, up and down through the day/night cycle. Alkaline condition fishes would handle this fine. Your Cardinals mightn't be so happy though.>
If I am unable to lower the pH significantly, should I abandon my plan to keep Cardinals?
<If you don't change the tank, perhaps you should try something better suited to alkaline conditions.>
I haven't been able to find much on whether they can be kept in water with this particular chemistry (low/medium hardness and alkalinity but high pH) and I don't want to force my fish to live in conditions that will make them unhappy or stressed. If you have any other suggestions for similar shoaling fish that would be happier in these tank conditions then I would also be grateful for those.
<It's actually not the pH that matters, but the hardness. Fish don't really care about the pH anything like as much as people think. Provided the hardness was low to medium, farmed Cardinals could adapt, regardless of the slightly basic pH. I just can't be 100% sure.>
Many thanks for your time and advice.
<Hope this helps. Neale.>
<<A brief/kibitzing note to look for cultured (orient) specimens rather than wild-caught (Amazon) Cardinals here; as they may well be more hard-water tolerant. BobF>>
Re: Issues With High pH, Suitable for Cardinals?      4/17/19

That has not entirely been my experience, Bob. What they gain in adaptability, they seem to lose in exposure to Pleistophora. My avowed preference is for wild-caught Cardinals, isolated from Neons at all points, and maintained in soft to moderately soft, more or less acidic to neutral water chemistry.
<I see; and only have much experience w/ ones produced in Singapore; always disassociated w/ Neons>
If medium hardness (or more so) water is inescapable, there are much better options: Pristella maxillaris, False Penguin Tetras, and Emperor Tetras.
All these handle medium to hard water well. Do also rate the old-timey Cherry Barb as an excellent Southeast Asian alternative.
Cheers, Neale
<Thank you (as always) for sharing. BobF>

cardinal tetras with clear blisters and tiny white worms     6/8/13
Hi Crew,
I have a planted 13 gallon tank....well established for 2 yrs.  2 of my 7 cardinal tetras have developed clear bubble like blisters (mostly near their pectoral fins and mouths). On close inspection there appear to be tiny white worms within or just adjacent to these blisters.  My other species (Ram, Corys, platy) are unaffected.
<Mmm, could be... Nematodes, other>
Others have posted about this problem on other websites but there are no definitive opinions on diagnosis or treatment.  I am suspecting they are tiny roundworms.  It is interesting that this seems somewhat unique to cardinals.
<Yes; possibly>
Any suggestions would be appreciated. If I can get a good picture I will send it.
<If you can, please do>
kind regards,
<I would try introducing an anthelminthic via foods... lacing ahead of offering. Okay for all to consume. Likely Praziquantel would be my/your first compound to trial. Bob Fenner>

Cardinal tetra with tumor just below its mouth    3/3/13
Hi there www crew,
hope all is well with you.
I have attached photos of a cardinal tetra I have had for several months. 
It has been slowly developing a mass just below the mouth.  He is otherwise fine and eating well.  The others in the shoal are fine.  It is a well established planted tank. Do you have any ideas as to a specific diagnosis?
<There's a small chance that this is Columnaris, in which case you could treat with an appropriate medication (it's a gram-negative bacterium, so choose with that in mind). Kanamycin and tetracycline are ideal. If the fish can still feed, then any lasting damage after treatment will be more cosmetic than anything else. But do bear in mind Columnaris is hard to treat, harder than common Finrot. However, Columnaris usually comes about quickly, rather than across many months, which would indeed seem to suggest a cyst of some sort. These are untreatable, and if the fish is suffering, it should be euthanised (a litre of aquarium water with 30 drops clove oil stirred into it makes a good "killing bath" that destroys fish humanely).
Cheers, Neale.>

A question for Mr. Neale Monks, Cardinal Tetras sys. (hard water) (Bob F., maybe you know better?) <<>>     8/29/12
Dear Mr. Monks,
I have been reading up your article about hard water in freshwater tanks:
This following passage caught my attention: "Dissection of neon and cardinal tetras has revealed damaged kidneys in specimens kept in hard water aquaria."
That cardinals and neons do best in soft water was part of my "basic knowledge set" of aquarium keeping, but an online forum I have stumbled across recently have very "respected" posters claiming that because they have managed to keep cardinals alive for 6 years in hard water showing nice colours, it proves that cardinal tetras do just fine in hard water.
<<Eugene; what is stated as "hard" water... alkalinity, GH, KH...?>>
This of course goes contrary to much of the advice given and data that is often thrown around in literature, online or otherwise.
Could you perhaps help me out in this discussion by citing the source of the findings of the dissection? It would be of great interest to me to dig deeper and enrich the admittedly superficial knowledge I have as an "ordinary" aquarist.
Best regards
<Hello Eugene. I read the mentioning of the kidney problems in Cardinals and Neons from an aquarium encyclopaedia of the 80s, but I can't remember which one! I'm on vacation at the moment so can't look at my collection of books to try to find the quote. But a quick look on Google Books reveals a few mentions of the "calcium salts in the kidney" problem with regard to Neons and Cardinals, for example in Baensch's Aquarium Atlas 1 and a copy of Tropical Fish Hobbyist magazine from the mid 80s (vol. 35, but can't tell which issue). This latter suggests the calcium salts were spotted by one biologist who dissected the fish (the source is mentioned as one "Dr Schubert" there) and then informed the author of the TFH magazine article.
I don't have this magazine so can't read the whole article. Likely this "factoid" has been repeated by other writers thereafter, as in Freshwater Aquarium Models by John Tullock, first published in 2006. I haven't been able to find anything specifically about this problem in the modern scientific literature, though I haven't spent much time look either! But with that said, a little time spent using the search terms "Paracheirodon" and "hardness" on Google Scholar reveals some interesting papers, such as a short paper called "The red neon, Paracheirodon axelrodi (Schultz, 1956), is able to survive in distilled water" that reports not only that the Cardinal can survive in pure water for significant periods of time but breeds best when spawning takes place in pure water! In any case, I believe that the poor survival rates of Neons these days has less to do with water chemistry and more to do with their poor quality and often poor care at all steps in the retail and hobby chain. Neons can certainly do well at moderate hardness around the 10-12 degree dH mark, which would be about pH 7-7.5 in most cases. But Neons are bred to a price rather than a quality, overstocked on farms and retail tanks, sold as beginners fish, and usually kept much too warm all along the chain (they prefer cool water, 22-24 C/72-75 F). Neon Tetra Disease may be a real threat in many cases -- it certainly spreads very rapidly if infected fish are not immediately removed -- but many sick fish seem to be suffering from opportunistic bacteria rather than the Pleistophora parasite, in which case environmental stress is surely a major factor. To be honest, I stopped recommending Neons many years ago. On the other hand, Cardinals are largely wild-caught,
<<Considerable numbers are now captive produced... have seen many millions in Singapore>>
 and if kept in warm, soft, acidic water are not difficult to keep and should live for 3-4 years without any problems at all. Hope this helps, Neale.>
Re: Question and comment re A question for Mr. Neale Monks (Bob F., maybe you know better?) Cardinals, hard water    8/31/12

Thank you both for your help.
<Welcome Gene>
<<Eugene; what is stated as "hard" water... alkalinity, GH, KH...?>>
The claims come from somebody who kept Cardinals in KH 6, GH 14 water.
<Mmm, moderate...>

He keeps telling me because they lived for 6 years, the conclusion is that they do fine in hard water.
<I'd agree>
The magazine Mr. Monks makes mention of "captive bred strains" of P. axelrodi in the USSR, that they seem to be more resilient in this regard.
<And to this. Those bred/reared and shipped through Singapore appear to be fine in harder water>
I am in Berlin, Germany, and the ex-East Bloc is just a stone's throw away, literally (Berlin wall and so on) - my local fish dealer told me that he gets his Cardinals from the Czech Republic, but is not sure if they are wild-caught imports or captive-bred.
<I want to make the comment that the last 10--20 years shows at
Nuremberg/Nurnberg, have shown many fishes, plants, live foods cultured in the Czech Republic>
Could it be that the Czechs are carrying on the "tradition" of successfully breeding Cardinals?
<I would not be surprised at all. In fact there are some Net reports of such:
Best regards,
<And you, Bob Fenner>

cardinal tetras in a discus tank   6/12/12
<Hi there>
I just read your post regarding the keeping of cardinal tetras.  So you've never had any problems with your adult discus preying on your cardinal tetras?  Do you also keep angelfish with your discus?  Would they prey on your cardinals too?
<I have had both Cichlids eat cardinals if there was too large a size discrepancy, not enough space, the cardinals added to the tank already occupied, or the former especially hungry>
<And you, Bob Fenner> 

Research on Cardinal Tetra re: food and light   3/2/12
I am doing research  at the University of the Western Cape to see if Cardinal Tetra can be trained to expect food just after a light has been turned on in their tank. Please can you direct me I have had very little success searching the web.
www.artvarkie.co.za  <neat>
<Best for you to seek the assistance of a reference librarian, have them help you formulate a computer-based bibliographic search strategy. Please read here re: http://www.wetwebmedia.com/litsrchart.htm
Bob Fenner>

Re P. pulcher biffo debrief and now a parasite! 2/20/12
Thanks a lot Neale,
<Ah, someone who can still spell "a lot"! Seems to be increasingly rare these days>
You confirmed most of my suspicions about what may have been going on re: the Kribs acting like Mr. and Mrs. Smith, plus its interesting to know that Kribs operate effectively as harem spawners in the wild.
<Quite so. Was a surprise to me when I learned about this. Do try and find books such as "The Cichlid Aquarium" for more.>
My pair split parental duties for the first set of fry amicably, with the female taking the lead. So far this time around it's definitely a female-only affair, with the male hiding in another cave and pretty much keeping out of the way while his wounds heal. He is getting better though. Hopefully he's learnt his lesson to stay away for next time - amazing how the female really beat up on him, even though he's half as big again as she is.
<"The female of the species is more deadly than the male...">
Another issue falling into the category of never-seen-before has cropped up in my 15 gallon tank recently. Inhabitants are 13 Cardinal tetra and 3 Amano shrimp, parameters NH3 - 0, NO2 - 0, NO3 - 10-15 ppm, pH 7.2, KH 3, 28 deg C. From consulting your dichotomous key, I suspect one of the cardinals to have a parasitic worm/fluke/fish louse attached to it (see picture). Being white, not red, leads me to believe it's not an anchor worm.
<I agree. A worm of some sort. Looks like a roundworm (nematode).>
Regarding treatment, I'm thinking a 35g/L salt bath (as per your article on the subject of salt use) OR some kind of commercial medicine.
<Hmm, would try a seawater dip first, as you say. Usually these worms can't reinfect fish in aquaria because of a missing host. Some exceptions, like Camallanus, but worth a shot.>
Can you recommend a course of action? Does the whole tank need treating or just the individual fish?
<Individual fish in terms of dips; otherwise, a standard anti-helminth like Praziquantel or Levamisole for the whole tank.>
Thanks a heap crew.
All the best,
<Cheers, Neale.>

Cardinal tetra twitching 9/12/11
Hello there,
I first want to say I'm so glad to have come across this group. There are tons out there but none are as right on as you guys (and girls). So starting from the beginning, I have had my community tank for about 4 years, 30 gallon. So the fish are not the originals but the set up is.
Right now I have 6 cardinal tetras and 6 albino Corys (well 5 as of 3 days ago.) The one Cory that just past away was a baby, 4 months old. He never grew over an inch long, which I thought was unusual though I have nothing to base my opinion on. It was the only egg left that I could save before mom and dad ate the rest. Needless to say it breaks my heart to even talk about the loss of little Tiki. I only mention it because it may be useful information for you to know.
<About it and you>
So about 2 weeks ago I transferred everyone and everything to a new tank, a 45 gallon. I even waited to change the filter to make sure nothing went wrong. I only use R.O. water,
<Not suitable>
rime for water changes, and Seachem mineral powder to add KH and GH to the water. I never add aquarium salt due to the Corys, (always thought they could not tolerate it, is that true?)
<Some species to some extent>
My readings right after Tiki's death were 0 Amm, 0 Nitrites, and 10 or 20 Nitrates (I had a hard time reading the difference on the color chart) the GH 0-50 and KH 3. I know that's a little too low but the mineral supplement says not to go by the reading because some of GH/KH are not detectable, does that sound right?
<... no. There is hardness or not... measurable>
My problem is two of my cardinals seem to be stressed, they are opening and closing their mouths more than the others and have faster more jerk like movements than normal, almost like they have to paddle more to stay horizontal.
<The RO>
They are also the smallest, males maybe?
I have had all six of the cardinals for 1.5 years and the Corys for about a year. Any ideas what could be going on? Thanks so much for taking the time to help all us fish lovers out!
<Am surprised to find detectable alkalinity w/ a system w/ reverse osmosis water in use... What shall we say to you? What manner of instruction might serve to waken to your consciousness... finishing Bob Fenner>
Re: Cardinal tetra twitching   9/13/2011

Thanks much Bob,
I kind of suspected the mineral ratio could be a problem. I used to have my aquarium professionally cleaned so I was following instruction...so I thought, obviously I missed a step somewhere. I thought they used RO with Seachem Equilibrium or sometimes Kent RO right. (I put in 1 teaspoon for every 5gallons). Are you thinking that is why my albino Cory baby never grew?
<Could well be>
I am going to do another water change today. I got some hard water from the well by bypassing the softener and it's testing 25° GH and over 400ppm KH. Would you recommend a 1 to 10 ratio from here on out with hard and RO combined or should I just add a gallon every fourth change?
<The latter would be my approach>
Thanks again - Katie
<Welcome. BobF>

Sickly Cardinal Tetras (was: Re: Panther Crab)  2/19/11
Ok well, you probably remember when I sent a question regarding my crabs death, but now my Neons are dying too!
<Oh dear.>
Before my crab died he was acting very strangely, usually he would always be hiding and never would come out while any light was on. He would wait for absolute darkness. Then for the last maybe five days of his life he was always out in the light, and he would just climb this plant or a plant that looked like this one (Picture at top).
<Nothing attached. Do remember to keep images small, 500 KB or so.>
He was decently large and the plant was not too supportive so I don't know how he was supported by it, but that's all he would do. Sit at the top of that plant day and night and do literally nothing else.
<Trying to get out'¦?>
Then he died and fell to the bottom of the tank. I then bought a moss ball since it looked quite nice, but it ended up being full of mold and was disintegrating, so I threw it out.
<Moss Balls do need quite specific conditions -- cold not tropical temperatures, lots of water circulation, and medium to bright light.>
About a week after that happened all my fish (except Crayfish which are seeming to be unaffected) were growing green dots on them! All of those smaller red fish that I had before have disappeared before this happened strangely. I don't know how they did it since my crab couldn't of eaten him and neither could my crayfish have since they are small crayfish that don't even have claws. The only other explanation is that my fish turned into cannibals'¦.
<No, but once sick or dead, they may well be nibbled on by others.>
Already maybe 3 tetras have died and one looks like it is on the verge of death, since its body is turning a glowing green which happens before they die and is just floating around and swimming upside down, not really caring what direction he goes in. What exactly is going on, could it of come from my crab? Was he already infected and that was the cause of his death? Or could of the disease come from the dead crab? Was it my moss ball? If not what other objects could it of been, and how can I fix it?
<Almost certainly your aquarium simply isn't being maintained properly. Can't offer anything useful without data. For now, let's review the needs of Cardinal Tetras. Firstly, the water must be very soft, 1-3 degrees dH is ideal, and no more than 10 degrees dH at the most. The pH needs to be on the acidic side, 6.0-7.0, but NEVER change the pH without first lowering the hardness (including the carbonate hardness) AND fully understanding what general hardness, carbonate hardness, and pH are all about. Temperature should be medium-high, around 28 C/82 is ideal. Water circulation should be very gentle, preferably air-powered. Any aquarium suitable for Crayfish will be unsuitable for Cardinals because they need COMPLETELY different things. That your Crayfish is still healthy may be a clue. Hope this clears things up for you. Cheers, Neale.> 

parasitic worm infecting cardinal tetras? (RMF, other ideas?)<<Sporozoans, Microsporideans?>>  2/19/11
Dear Crew,
Hoping you can help me - I've scoured the site and can't find anything that accurately describes the situation we currently have. Last night I noticed that one of my cardinal tetras had a fluid filed sac protruding from just underneath the gills on one side,
<Do occasionally happen, for no obvious reason I'm aware of, though the usual culprits such as physical damage, stress, and parasites of various sorts can be considered.>
the fish doesn't seem to be in any discomfort and we observed it feeding ok, however on closer inspection of the other cardinals we've noticed that three of them appear to be affected by some form of worm - the fish are each showing one large 'blister' of around 3mm on their sides which appear to have a thin white worm inside, no more than 1mm in diameter. We tried unsuccessfully to remove the affected individuals from the tank last night, when examining the fish this morning one of the blisters appears to have ruptured as it now resembles a wound rather than a blister, and I noticed one of the worms attached to another tetra, but without the surrounding blister.
<Indeed. My guess would be that the blister rather than the "worm" will be the healthcare issue, because most worm-like infections can't actually complete their life cycle under aquarium conditions. They need intermediate hosts like birds or snails for that to happen.>
The tank is a 500l (134 US gallons, or 110 UK gallons) tropical freshwater system, heavily planted and is maintained at 25-26 Celsius (77-78.8 F). Ammonia, nitrite and nitrate are all undetectable, and we do 15% water changes weekly (including gravel siphoning). The current stock are:
shoal of mixed tetras (15 cardinal,
<Angelfish food.>
5 lemon, 5 Pristellas, 3 Congo)
10 juvenile angelfish (1.5 inch body length)
6 Corydoras catfish
6 Bristlenose catfish
So far the only fish that seem affected are the cardinals but I suspect if it is a parasite without a specific host then it will spread to the other fish in the tank.
Currently, the plan is to increase the number of water changes to reduce parasite load in the tank
<Water changes are a good idea for other reasons, but won't really dilute the concentration of parasites in any meaningful way.>
however am not sure whether we should also treat the tank with an anti-parasitic medication as well, and if so what would be best? We've not been able to get a photo of the affected fish but hoping you might be able to offer some advice without one'¦
Here's hoping,
<Would recommend nothing more than acting as per physical damage for now: observe the fish, and if they show signs of their wounds not healing, medicate with something like the excellent eSHa 2000 Finrot/Fungus medication. Without a positive ID on the parasite, medicating further would likely be pointless and could well stress the fish still further. Cheers, Neale.> 

Update on sick Cardinal    1/20/11
As I was typing my first email, my Cardinal died. I found him floating in the Hornwort...which maybe is a blessing because no one got a chance to snack on him. I have been reading fish diseases/symptoms all morning and I can't figure out what it could have been. He wasn't eating at all either.
Please, if anyone has any ideas what it could be. Nothing new has been added to the tank in months..the last was a batch of cardinals and everyone was ok. I'm am so upset and worried I may lose my entire school of Cardinals.
Thanks so much for your time,
<Hello Laurie. Cardinal Tetras don't live long in hard, alkaline water. So first make sure your water is soft and acidic. Ideally, 2-5 degrees dH, pH 6.5. At the hardest, the water should be 10 degrees dH, pH 7. Anything harder than that, i.e., moderately hard or hard, and the Cardinals will die off one by one, usually across a few months. Secondly, they are somewhat prone to Neon Tetra Disease. Perhaps less so than Neons, but prone nonetheless. There is no cure. The disease is transmitted by healthy fish nibbling on dying or dead fish. Remove sickly fish at once, and destroy humanely (30 drops of clove oil in a litre of aquarium water works well; see the WWM article on Euthanasia for more). Cheers, Neale.>
... FW... pH...
 -- 1/20/11
Dear Neale,
My ph is generally between 6 and 6.5.
<Do check the pH is stable'¦ biological filter bacteria aren't happy below pH 6.5, and from 6.0 downwards may not work at all. The use of a pH buffer to fix the pH at 6.5 is useful.>
I use a mix of RO water and tap. Any idea what the black splotches could be, as per my first note?
<Black blotches are commonly ammonia burns'¦ possible if the biological filter is working poorly or intermittently. Do see ammonia burns on Goldfish for examples. Very common in bowls and unfiltered tanks. Otherwise some sort of secondary infection perhaps. Not sure. Black patches aren't a common symptom. Almost all the Cardinals I've seen die have done so through wrong water chemistry and/or Neon Tetra Disease. Stress from handling, tankmates, etc., can also be factors. Do check water temperature is on the muggy side, 28 C is about perfect, and that water current is minimal. Overhead light should be filtered through floating plants or otherwise minimal. Cardinals come from sluggish, shady streams and react badly to bright, open, fast-water maintenance. Despite their wide sale, they adapt poorly to the average community tank, hence their reputation as being "delicate" fish.>
I'm sick over this,
<Agreed, and I have largely given up with this species and even more so the Neon as far too difficult to maintain.>
<Cheers, Neale.>

my cardinal tetra is sick  3/8/10
Hi , I just bought 15 cardinal tetras for my 25 gallon heavily planted aquarium I already had 17 neon's
<Neons generally don't like the warm water required by Gouramis, so be careful here. Neons are happiest at 22-24 C, whereas Dwarf Gouramis need around 28 C. It's hard to please them both at the same time, one reason
both species are often considered "delicate" fish.>
and 1 dwarf Gourami ( I think I spelled Gourami wrong),
<Indeed, it's Gourami.>
but I put the cardinal's in the tank and at first I thought they were just stressed because being in a new tank and 1 died shortly
<Cardinals also need warm water, and shouldn't be combined with Neons. Cardinals need soft, acidic water at about 28 C, and Neons prefer cooler water and more soft to moderately hard, slightly acidic to neutral water.>
and 3 more got sick they started to get distressed and 2 more died 1 of them before I quarantined them and 1 after
<If these fish are dying within days of purchase, they may have been in bad shape before you bought them. But that said, if your aquarium is very different in water chemistry and water quality to the conditions in the retailer's tank, then moving them could be stressful. Just to recap, you need 0 ammonia and 0 nitrite.>
it looked like the scales around their head and gill's were coming loose, the 1 is still alive and is no longer distressed an has colored up, but, it still has the weird stuff on its gills and head , it does not look like worms or neon tetra disease and it has me stumped ! Please Help !
<Difficult to say anything sensible without a photo. Cardinals generally don't get Neon Tetra Disease, though it happens sometimes. Cardinals are sensitive to poor water quality, and they never do well in hard water. If you decide to send a photo, to remember, keep photos to 500 KB. That may mean you need to resize them in iPhoto or whatever.>
No other fish have it, but I'd like to have an idea what it is and how I can treat it just in case it show's up on any other fish ! Thanks.
<Review water quality, chemistry. Check water temperature. Do make sure the Cardinals aren't being attacked or bullied. Cheers, Neale.>
re: my cardinal tetra is sick  3/8/10
Hey, thanks for all the tips they were very helpful .
I added some salt and sodium bicarbonate an Epsom salt to the quarantine tank (my grandpas advice he has had tanks all his life and has bread neon's and cardinals and other freshwater fish)
<He bred Cardinals? That's pretty impressive! In any case, salt may have a slight beneficial effect, but sodium bicarbonate hardens water, and that's usually a bad thing so far as Cardinals and Neons are concerned. If your
water was insanely soft, and pH was bouncing around wildly, then hardening it a bit would help. But otherwise neither sodium bicarbonate nor Epsom salt serve any great purpose.
and the fish seems to be getting better, the weird scales or whatever they are starting to go away the fish is more active ! If the stuff comes back I'll send a Photo and see what your thoughts are.
Thanks again!
<Cheers, Neale.>

Cardinal tetra gaping 2/4/2010
Dear Crew,
Wondered if you could shed some light on a problem I've noticed with one of my cardinal tetras - for the last few weeks the fish has been gaping and doesn't close its mouth, although it appears to be feeding without problems.
<Yes, have seen this problem. Precise causes unclear to me. Possibly genetic if the tetra has always been like this, the lower jaw simply not properly developed. While most Cardinals were wild-caught in the past, breeding on farms is increasing, and like Neons, farms tend to produce fish to a price rather than a standard.>
I noticed the same problem with another cardinal about 3 weeks ago, however that fish was in a bad way (swollen abdomen although scales not sticking out, seemed to lack balance and died very quickly after the problem first
<The thing with Cardinals is that they have very specific needs. They must be kept in soft water, and simply don't do well in hard water. They also need quite warm water. In this regard they're the opposite of Neons, which
need quite cool water. You're aiming for a pH around 6.5, hardness around 5 degrees dH and certainly no more than 10 degrees dH. The temperature should be around 28 C.>
The cardinals live in a 110gallon tank with a variety of other tetras (10 head and tail light tetra, 10 Pristella tetra, 20 green neon tetras), two dwarf bristle nosed catfish and 7 Cory catfish.
<Corydoras spp. don't like such warm water, with the exception of Corydoras sterbai, so be careful here. If they're constantly darting to the surface to gulp air, that means they're feeling stressed.>
I've not seen any aggression between any of the tankmates, they all feed well and all swim to the side of the tank when anyone passes by so they're all good and alert! Ammonia is 0, nitrite also 0 and nitrate currently at 5ppm, the tank is heavily planted with some bog wood to provide cover and is kept at a temperature of 28C (82F - we have a small group of young discus currently finishing QT before being added, however they're staying there till I know everything is well!).
Did wonder if the two affected fish may have fought each other and damaged their mouths as a result? The problem first surfaced while they were living in a 40l Nano while the larger system was being set up and cycled.
<It's possible this is related to exposure to poor water quality, but to be honest I don't think so. Usually fish with dislocated jaws get into that state by fighting, but it's hard to imagine that's the case with Cardinals.
In any case, there's no "treatment" as such, and if the fish can't feed, it'll need to be euthanised. Otherwise, it's a case of wait for the fish to get better by itself, perhaps as whatever damage or swelling gets undone.>
Hope this all makes sense,
<Cheers, Neale.>

Shrimp and cardinal tetras   12/6/09
Dear aqua experts,
<Hello Janet,>
I have only found conflicting advice in trying to find the answer to my question, so I come to you to get my answer. I have 2 established freshwater tanks. The 10 gallon houses 14 red cherry and Amano shrimp as well as 10 zebra Danios that are about 6 weeks old and growing.
<Very good.>
The 20 gallon houses 3 zebra Danios and 6 cardinal tetras.
<I'd up the number of Cardinals if you could. I'd also make the observation that Danios prefer cooler water to the Cardinals, so one or other group of fish isn't going to be completely happy. 25-26 C would be about the best
compromise, but even then, not ideal.>
I would like to move the Danio juveniles into the 20 gallon with their parents and have a Danio-only tank.
<Very wise. Danios like things on the cool side, around 22-24 C.>
I would like to move the cardinals into the shrimp tank.
Both tanks are planted, the 10 gallon heavily. I'm sure (?) the shrimp are very happy in their current tank with only some baby Danios to keep them company. Can I add the cardinals to the shrimp tank (after I move the baby
Danios) without the shrimp becoming reclusive, boring, anxious and eaten?
<Yes; Cardinals pose minimal threat to the Shrimps, even Cherry Shrimps, and the two species will coexist nicely. Since Amano shrimps like things a little on the cool side, they're ideally kept with Danios rather than Cardinals.>
Thank you all knowing ones.
<Cheers, Neale.>

Good tankmates for Cardinal tetras  10/8/09
Hi: I have 12 Cardinal tetras and 1 Bristlenose Pleco in a 37 gallon planted tank. PH in the tank is 6.5 and the temperature is 80-82 degrees Fahrenheit.
<Sounds great.>
I'm looking for tankmates that are a little more active than the Cardinals but won't eat my tetras or harass them or overload my tank.
<Indeed. Good choices might be found among the dwarf cichlids. I'd avoid Mikrogeophagus ramirezi because the quality of the stock sold in pet stores is incredibly low, and instead look at things like Apistogramma cacatuoides, a wonderful little cichlid that does fine up to 28 C/82 F.
Apistogramma cacatuoides is available in several colour varieties such as "triple red" and "half orange". It is also, exceptionally for Apistogramma, relatively hardy and easily maintained. Apistogramma are generally harem fish, so to avoid chaos and aggression, keep one male to two or more females. Each specimen will expect a cave of its own; flower pots, hollow ornaments, and halved coconut shells all work well.>
My LFS has Electric Blue Jack Dempsey's. They told me the those would be o.k.
<The retailer who told you this is an idiot. Rocio octofasciata is an extremely aggressive hard water cichlid in no way suitable for a planted community aquarium like yours.>
tankmates for the Cardinals but it seems they would eat them when they were full grown.
<Among other potential problems, yes indeed...>
Can you recommend something?
Thanks for your time.
Marilyn V.
<Cheers, Neale.>

Re: Good tankmates for Cardinal tetras  10/9/09
Thanks Neale. Those are beautiful fish. Can't wait to get some.
<Yes, they are lovely fish. Do take some time to hunt down good quality stock. Some of the specialist cichlid forums and clubs in your particular part of the world may be able to help you find good breeders and
<Cheers, Neale.>

Paracheirodon axelrodi question, stkg.   9/21/09
Hi! I plan to set up a Bow front 16 gallon (tall) tank with live plants and a driftwood centerpiece, to serve as a species tank (except for a black Kuhli loach) for Cardinal tetras. My question is, how many would be suitable to add, and what would be more suitable, Cardinals or Neons? And what kind of plants would be best to add? (My pH. s around 7.5-8.0, with lights that came with the tank. Thanks! -Jack
<I'd go with Cardinals. Two reasons. Firstly, they do better in warm water than Neons, which prefer cooler water (around 22-24 C) than Kuhli loaches enjoy. Secondly, they're generally hardier, partly because they're wild-caught rather than farmed (and the quality of farmed Neons varies wildly) and partly because they don't seem to prone to Neon Tetra Disease.
Allow about one Cardinal per gallon. If all seems well, you could even up this a bit, to around 20. Cheers, Neale.>

Did Neale write a Cardinal Tetra article?   5/4/09
Hi! Did Neale write an article about Cardinal Tetras in one of the American fish magazines a month or so back? I am wondering if I am missing an issue.
<Hi Michelle. Yes, I did write an article on Cardinals (and I think Neons too) for 'Aquarium Fish International' magazine, an American magazine based in California. It was scheduled for the March 2009 issue. Cheers, Neale.>

Re: Did Neale write a Cardinal Tetra article?   5/4/09
Thanks for the reply! I'm going to give them a shout.
<Hi Michelle. I suspect the issue with the article might be in the shops now; some copies of the magazine have apparently been delivered to my 'back-up' address in the US. Cheers, Neale.>

Keeping Rams and Neon/cardinal tetras. Sel., sys. mostly  1/24/09 I have a basement tank, 36/ 18 by 14, 52 gallons. I plan on using a river sand bottom, <Soft sand will be appreciated; the name Mikrogeophagus means "little Eartheater", and like the true Geophagines cichlids, these fish (in the wild) sift the sand for algae, invertebrates and decaying organic material.> my tap pH is around 6.8 to 7. but I plan on using RO water (With a ph of 6.0), they make for you at World of fish, (its voted best LFS in twin cities). At the store they sell blue angel rams, $30 a pair, from a local breeder. These fish look much better, more vigorous and brightly colored then the regular rams they also sell (blue/German) they keep the angel rams in RO water but the others they do not. <Locally bred fish infinitely better and worth the expense. Farmed Mikrogeophagus ramirezi are of variable quality and often "juiced" with hormones and antibiotics; consequently their survival rate after shipping is dismal, even though they look nice in the shops.> The tank they are in is labeled NFS, as they are treating for ich, but all fish on the mend, no signs of ich on the rams at all (Corys had it), rams are showing territorial/natural behavior and they use the same RO, water I'll be using if I get them, at the shop. <If you have locally bred fish available, buying farmed specimens would be dumb.> I'm planning on buying a high intense light, and planting with live plants and driftwood. What kinds of plant do Rams like or that grow well in their water? <In the wild they live in sun-baked shallow pools with mostly amphibious vegetation that mostly grows above the waterline. So there's not really much "authentic" you can go for. Instead, concentrate on species that will tolerate the conditions in the aquarium. The very high temperature (minimum 28 C/82 F) will stress some plant species, while the necessary soft water will stress others. To be honest, I'd probably go with floating plants initially, such as the Limnobium, and leave rocks and hollow ornaments across the bottom for the fish. If you wanted rooted plants, buy species in pots that you can easily fertilise with tablets since the sand itself will contain no nutrients (unless you put a layer of pond soil or whatever underneath the sand). Cryptocoryne species would be ideal.> What are good foods for these guys? <These are quite fussy fish that tend to have favourite foods. I've never seen Mikrogeophagus show much interest in flake or pellets, though I dare say some will eat the stuff. Mostly they seem to require a varied diet of live or (wet) frozen foods: bloodworms, Glassworms, mosquito larvae, daphnia, etc. Remember to vary the diet; if they get just bloodworms, you're setting them up for a vitamin deficiency in the long term.> I talked to the staff at the LFS and they said add tetras first after cycling then wait a month or more before aiding rams/ change like 5 to 10% of the water a week. <Likely far too little in terms of water changes. Mikrogeophagus ramirezi are acutely sensitive to nitrate, and tend to develop things like Hexamita at the first sniff of high levels of nitrate. In part this is surely why they die so quickly in most community tanks. So rather than estimating a water change, grab a nitrate kit and keep track of the nitrate level each week for the first few months. You'll get a picture of how quickly nitrate levels rise, and can act accordingly. You're aiming for under 20 mg/l nitrate, and ideally 0-10 mg/l. Part of this is avoiding overfeeding: these fish need only small amounts of food to do well.> I was think 1 or 2 pairs of rams and 12 to 15 tetras in a school. <Ok.> I was wondering if a school of neon, rummy nose or cardinal tetras would be good dithers ? Are there any other good tetra-like fish to keep with them or is it best to keep the Angel rams separate? <Neons need cool water, so they're not an option for use alongside the warmth-loving Mikrogeophagus ramirezi. Cardinals can work well, and probably make the best bet. Rummynose tetras would be good in some ways, but they're hyperactive fish, and need to be kept in a decent sized group to school properly; if they just mill about looking nervous, that'll have the reverse effect on your Mikrogeophagus. If you don't mind switching continents, Harlequin Rasboras work well too.> I do understand the fancy type of rams are less hardy but I will be moving in five years + anyway.( though I am planning on taking the tank with) <You'd be lucky if most of the farmed specimens last 5 months, to be honest. They really are abysmally poor fish. I wouldn't touch them with a barge pole. Like pouring money down a drain.> thanks <Cheers, Neale.>

Re: Keeping Rams and Neon/cardinal tetras. 1/24/09 Thanks I will research more, I'll also make a video of it- the tank I mean. <Sounds good. Look forward to hearing/seeing more in due course. Do try and pick up one of the books on Dwarf Cichlids, there are many. Even the old TFH one by Jorg Vierke (used, less than two dollars on Amazon) will be a useful read in terms of understanding the ecology of these fish in the wild and their specific requirements in captivity. Mikrogeophagus ramirezi are nice fish, but the reality is most people fail to keep them alive for more than a few months, at best. Cheers, Neale.>

Re: Keeping Rams and Neon/cardinal tetras. 1/24/09 When/if I get them should I use jungle parasite clear on them when they go into the main tank, or should I use a separate, tank.? <"Scattergun" approaches to healthcare rarely work. Quarantine all new livestock, and if signs of illness appear, diagnose and treat as required. The main killer with Mikrogeophagus ramirezi is Hexamita, and it is likely latent in all specimens, certainly those produced on fish farms. Hexamita becomes a problem when the fish are kept too cold, exposed to high nitrates, given a poor diet.> Also is it better to use fake plants then live? <No difference so far as the fish are concerned. Use whichever you want.> I know if I did so it would save on lighting and help reduce care in an already "Demanding" setup. <Cichlids would prefer tanks without lights at all, so do whatever you want so long as there are shady places for the fish to swim. Cheers, Neale.>

Re: Keeping Rams and Neon/cardinal tetras, Ram sel.    1/28/09 Do you know of any local Ram breeders that sell decent/or excellent quality rams? I'm going to wait a few years before getting them, but I wanted to look for breeders. I live in St Paul MN. <Well, since I live in Hertfordshire, England, I'm afraid I can't comment on the local fish breeders in Minnesota. Obviously the first step is to find your city or state fish or aquarium club, and get in touch with them. There is certainly a Minnesota Aquarium Society for example: http://www.mn-aquarium.org/ Join up and attend their meetings. They'll surely be able to get you in touch with people in your area who breed fish. One of the great things about this approach is that the people in aquarium clubs are typically advanced hobbyists, and so are likely to be breeding fish you've never heard of, or don't see in aquarium shops. There are lots and lots of lovely dwarf cichlids that rarely get traded, so you might find some real treasures this way. Cheers, Neale.>

Sick Cardinal Tetra, env. likely   10/22/08 Dear Crew: I always appreciate your articles and help from time to time. I hope you can help me again. <I as well> I've looked and looked and can find nothing that helps me identify what's wrong with one of my cardinals. In a 10 gallon tank, I have: <Mmm, small/er volumes are hard to keep stable, optimized... a bigger tank would be better> 9 cardinals - most are about 1.5 inches. Have had most of these since July of this year, when this tank was established. 2 Otocinclus 2 Corydoras julii Medium-not quite heavily planted with a little driftwood Aquaclear 5-20 filter -well-maintained Ammonia 0 Nitrates 0 Nitrites 0 pH 7.8 always tap water is usually 8 <Yikes... this is too high... and likely accommodated with high alkalinity. The fish life you list really appreciates lower pH, hardness... See WWM, Fishbase.org...> Temp 80 F Water changes 40% min at least once a week - usually twice a week. <Mmm, I would restrict such change out percentages to no more than 25%... use water that has been set out a few days to a week ahead of time before use... Again, gone over on WWM> Menu - fed twice a day - variety of flake, Hikari micro pellets, Tetra veggie crisps, Aquadyne flakes, live baby brine shrimp and the occasional crushed snail that shows up. Today, I noticed a orange-red spot near the head/cheek of one of the cardinals. It looks like a cyst of some sort - almost like an angry pimple. The spot protrudes from the skin and is about 2-3mm in circumference. The spot seems kind of clear or translucent (not fuzzy like fungus) and the center of the spot is more orange in color - like the head" of the pimple - like a bullseye with just one outer circle. <Mmmm> I have treated this tank for Ich in the past and I don't think this is Ich. No white spots on any of the fish. No flashing or fin clamping. Aside from the spot, they all seem fine. None of the other fish show any signs of it - yet. Usually very healthy. <Could easily be "something" brought in with the fish, even non-pathogenic> Nothing out of the ordinary - except about 4 days ago - our temp dropped a bit (60's at night in Orlando, FL) and I had to fiddle with the thermostat to get it to maintain at 79-80 F.. I usually maintain at 79, but the fluorescent compacts heat up the water too much, so I back off the heater. But I had to raise the heater this week as the night temps were too low. <Mmm... what wattage is this heater? They're thermostatic... should keep any given temperature... not add to outside heat sources> One morning the tank temp was 76 (before lights on) and then by late afternoon, it was 82. So I do know they have been stressed, but they seemed OK and I didn't notice anything until today. Temp has been stable again at 79 for the past 2 days. I see in some articles by Alesia Benedict that Cardinals like warmer temps. What is the ideal temp for them? <http://wetwebmedia.com/FWSubWebIndex/tetragonopterinae.htm 23-27 C.> Do you know what this is - and how do I get rid of it? <Mmm, nope... might help to see a pic, but likely would require dissection, microscopic examination> Any help you can offer is appreciated. With kind regards, Sandy <I would not try to "treat" this with a "medicine" Sandy... Instead, look to improving the environment here. See WWM re water hardness... perhaps starting here: http://wetwebmedia.com/FWSubWebIndex/fwsoftness.htm and the linked files above. Bob Fenner>

Re: Sick Cardinal Tetra 10/22/08 Thanks Bob. <Welcome Sandy> The spot is actually just behind his gill cover. Today, still none of the other fish seem affected. I do notice a small dull patch on the opposite side of this same fish - like something starting there as well. Tried to get a picture, but none are focused enough to show anything you could really see. <Hard to do, I know. Have seen similar markings many times on this species> I read the whole article and the other webpage. Thank you. My big problem is that our water supply is also buffered. <Mmm, best to start with cleaner water from filtration then... RO, perhaps RO/DI... and add just some (likely a tenth) of regular tap water to this> So any attempt to artificially adjust the pH would take a lot of adjustment, on a regular basis, and with each water change, and would likely stress the fish more than having them acclimate to the water supply. <A valid concern... but not hard to adapt/adopt a simple water softening routine... again, simply using a mix of cleaned up tap with just some regular re-added for minor buffering> These Cardinals - I was told - were farm raised in Florida and so should be "used to" our water - as much as they can, I suppose. <Mmm, I fully suspect that the water used for this species, and Discus... is actually greatly softened, has much of the TDS removed to facilitate spawning, rearing> I have looked into getting peat inserts for the filter and can find nothing in my area. Do you have any practical suggestions? <Again... reverse osmosis... We have "liquid rock" water here in S. Cal. as well and use such for most potable, cooking, and some house plant needs... the tap is quite unpalatable... I would argue, not really healthy for human use> The driftwood has been in for over a month and is releasing some tannins, as water changes show slightly yellowed water, but not enough to affect the pH. <It would do so if there was not so much alkaline reserve... again, captive systems are reductive... they tend to "go" acidic with time... But not with such high alkalinity> Will back off the water changes as suggested and will try to use aged water as much as possible. <Good> I would like to move these fish to a 20 long, and just keep this 10 as a quarantine/hospital tank. but that will take a while to accomplish. We'll have to live with this set up for at least a few months. Heater is a Marineland Stealth Submersible 50W. <Mmm... I would move up to a hundred watter here... and use it in your upcoming 20 long...> Do you think a salt dip would help - or hurt this little guy? <Hurt> Or do nothing and watch? <This is what I would do. BobF> Thanks again, Sandy

Re: Sick Cardinal Tetra 10/24/08
OK to all. Thanks again much. Will have to wait and see about the RO
system though.
Warm Regards,
<RO devices of a few models are a wave of the future... Very easy to install, operate... Useful for human uses to eliminate the vast majority of contaminant issues. Bob Fenner, who has used them for decades>

Tetras (Neons & cardinals) dying one by one in the dark in a planted aq.  8/7/08 I hope you can help. Please forgive the length, but I wanted to give you all the info I could think of. <OK.> 30g L, been up for about 8 weeks (cycled with seed filter from friends established tank), custom hood with AHsupply 96w CF bulb (3.2W/gal), eco-complete substrate mixed with fine gravel. Fluval 205 filter. Stealth 100W heater. <All sounds good.> Tank has the following plants (most of which are thriving): Cabomba (2 bunches of 5 stems each), Moneywort (4 bunches of 3 stems each), Melon Sword, Chain sword (just a baby), Microsword (2sq in patch), Ruffle plant, Wisteria (just finally establishing its fine submerged leaves - 1 bunch of 3-4 stems), Broad Ludwigia (1 bunch of 3-4 stems), small Java fern, small Anubias nana, and a large bunch (about 15-20 long stems) of Anacharis (from a friends established tank). Sounds crowded, but you'd be surprised how open it really still is. <At least some get pretty big -- Echinodorus osiris for example will quickly take over a 30 gallon tank if it thrives; mature plants can be 50 cm tall and 30 cm across! Echinodorus martii likewise.> To this there's the following fish: 5 spotted Corys, 6 Otos, 3 "mystery" snails, 6 zebra Danios, and originally 8 each Neons and cardinal tetras. <Right, well one issue here will be temperature. To wit, Neons prefer cool water, 20-24 degrees C; Cardinals need warm water, 25-28 C. There's no "happy medium" at which both can be expected to do perfectly well. Corydoras, Otocinclus and Danios are also cool-tropical fish, and will thrive at 20-24 C (I'd go for 22 C). But that's too low for the Cardinals. So one way or another, at least some fish are going to be heat or cold stressed.> The light is on a timer to cycle 6 hours on in the morning, followed by a 3 hour off break mid afternoon, then another 6 hrs on in the evening. Then off for the remaining 9hrs overnight. <OK.> All was well, the plants are thriving, the fish too. <Good.> Then I added the Anacharis about 2 weeks ago. Suddenly I'm missing cardinals and Neons overnight, just 1 or 2. at a time. Never noticed any trouble with the actions/attitudes of the tank mates, everyone pretty much sticks to their schools. But the losses continued. Everyone looked fine when the lights are on... healthy, active, feeding. It was great. Well it's a great mystery alright. <Well, Neons and to a lesser extent Cardinals can be plagued with "Neon Tetra Disease" and will drop off one by one until the cycle of infection is broken. But it is also possible the new plants brought in a predator, such as a Dragonfly nymph.> I finally started watching closer at night and I found that after the lights been off for about 90 minutes (+/- 15 minutes) I notice a gradual and frightening change. Both the cardinals and Neons lose nearly all coloration going nearly white/clear. <Quite normal.> Then one or two of them start going bonkers and lose their equilibrium swimming upside down, backwards and on their sides, barrel-rolls, tumbling end-over-end, etc., then death. <That is odd.> Turn the lights back on and gradually (within 20-40 minutes) all coloration has returned and activity resumes normally. <Ah, now, this is curious. Have you checked how pH is affected by photosynthesis? When plants photosynthesise they remove CO2 from the water, allowing the pH to rise. When they stop, CO2 accumulates and pH goes down. Alternatively, some (but only the minority) can perform "biogenic decalcification", and I believe Anacharis is one of them. What this means is that they remove carbonate and bicarbonate from the water as the source of carbon for photosynthesis instead of CO2. This is why these plants prefer hard water. Anyway, in the process the water loses its carbonate hardness and consequently its pH buffering capacity. The net result will be that pH will drop while these plants are photosynthesising, and the water pH will also become less stable with regard to other pH altering processes.> My water parameters have been rock solid since the beginning: Nitrite 0; Ammonia 0; Nitrate "nearly" 0; kH 5deg; GH 12deg; pH 7.6; chlor. 0. I've even tested right before and after a light cycle and saw no appreciable difference. Temp stays between 78.5 and 80.5F. <Do check the pH and carbonate hardness through the day to test my hypotheses above.> My thought were CO2 poisoning - but the zero change to pH leads me to believe the CO2 isn't reaching toxic levels. Second thought - The plants are using up all the available O2 (I'm not aerating) at night thereby starving the smaller, more sensitive tetras. So I added a small airstone to the corner of the tank and set a small air pump to kick on when the lights go out (my timer has day/night outlets). It didn't seem to help. <Leave CO2 off for a few days and see what happens. Won't harm the plants.> Last Saturday night was the worst, within 2-1/2 hours three tetras gone (down to 6 now, 2 cardinals & 4 Neons left), and all the fish (except the 5 Corys, 2 largest Danios, and 3 largest Otos) were pale. Even with nighttime aeration. <Hmm...> So as a stopgap measure I retooled the timer to cycle the light and dark to 3 hrs light, 2 hrs dark ('round the clock). Two nights of success now with no casualties... but even though there is the requisite "amount" of light and dark I cannot imagine the rapid time cycles are any good for either the fish or plants long-term. <It isn't good for the plants; they need a certain length of time simply too start photosynthesising, and 3 hours won't be enough.> My next attempt will be to get a larger air pump and drive an 18" bubble wand across the back of the tank rather than the small airstone driven by the smaller air pump. I know this will drive out more CO2 to the detriment of the plants (though probably not too much), but it should eliminate the worry of CO2 poisoning, and should add O2 in the dark for the plants and fish to (hopefully) share. Also, I'll be raising the filter spout up closer to the surface to provide a little more surface agitation (currently its about 2in below with no agitation). <Not sure this is the issue.> Finally, since this all started after adding the fastest grower in the largest number/mass plant-wise (the Anacharis). It's possible that plant addition might've pushed the balance over the edge with respect to CO2 and O2 respiration. So I'll be pulling that out and trimming it back to a more manageable (2-3 bunches of 4-5 "short" stems each) size. <Hmm...> Hopefully then I can gradually return to slowly extending the light/dark cycles to a more natural rhythm and keep my fish healthy and my plants growing. Any thoughts? other suggestions? etc? Anything I missed? Mark <Cheers, Neale.>

FW Cardinals, and something sinister- Stressed Fish Start To Have Problems 06/15/08 Hello WWM crew. First, I have to thank you again for this great resource- your time and expertise help so many people. You helped me a great deal in the past with the curious subcutaneous worms plaguing my Cardinal tetras. Thank you so much. < Thank you for your kind words.> Treating the tank with Seachem's Cupramine at ¾ of the recommended FW dose worked well; every single Cardinal pulled through! The only "casualties" were a clutch of eggs that my male M. altispinosus decided to eat despite his mate's valiant efforts at guarding them (they are usually a great breeding pair). That being said, something sinister seems to have creeped into the tank. About a week ago, I found a Cardinal looking emaciated and lethargic. He had hidden too well in the plants and I had not found him in time to effect any positive change. A few days later, a heat wave struck. When I arrived home, the temperature was close to 90 degrees F! Everyone was either floating oddly or lying on the bottom. Off with the lights, on went the AC, and I floated sealed bags of ice on the surface. Remarkably, everyone recovered fully except for one large female Cardinal, who I found the next morning. Yesterday, another Cardinal started "shedding"- imagine a dog shedding its winter coat, but a fish shedding its scales. He also appears to have Popeye! This evening, another Cardinal appears to have the beginnings of Popeye. One Cardinal could have been an isolated incident. The second could have been an accident. But four Cardinals within a little over a week? I DON'T like those odds. Everything sounds environmental, but- Ammonia = 0, Nitrite= 0, Nitrate=0 (aquarium is long established/cycled, I just have a lot of very happy plants), water is soft (RO mixed with tap, cleaned at least weekly), pH is 6.6, temperature is 82 degrees F. Is there something else that I should be testing for? Could there be another connection between these incidents? There has only been two recent change to the tank: one day before the first Cardinal's death, I added a new Fluval canister filter to the existing tank filtration (which remains in place), and I had begun using new ferts for the flora (iron enriched "Plant Gro" by Nutrafin, since I can't find Flourish with iron locally- but I do use Flourish root tabs). Coincidence, correlation or causation? Tank mates include: 28 Cardinals (not that I can actually count them) 4 M. altispinosus 3 Otocinclus (Very fat and happy) 1 Longfin Bristlenose Plec 1 SAE Last edition to the tank was the Plec, but I have had him for a long time and transferred him to my main tank because guests always commented on how beautiful he was. Everyone was quarantined for no less than one month prior to their introduction to the tank. Their diet (in case it is relevant at all'¦) consists of mashed peas, thawed frozen bloodworms, Nori (which I think they play with more than actually eat), Spirulina flakes, Tetra granules and Nutrafin Max flake food (and whatever eggs/fry tank mates manage to steal from the rams and the Otos). I would greatly appreciate any insight into my Cardinals' plight- advice, guidance, suggestions, musings, criticisms or reasons why atmospheric pressure is conducive to the integration of pachyderms into society. Thank you so much, and enjoy your weekend, Tianna < Here is what I think is going on. During the heat wave your fish and biological filtration were stressed. Oxygen levels were low and metabolism was up. Not a good combination. You fish may have somewhat recovered but the stress made them vulnerable to bacterial infections. For a short time period you probably didn't have much biological filtration because the beneficial bacteria died off during the heat wave. If nothing else their numbers may have been affected. As bacteria start to colonize the canister filter they consume oxygen. Some filters get to the point they consume all the dissolved oxygen going into the filter. Make sure that the return tube forces the returned water to the surface so it can be oxygenated. The infections can be treated with Furanace but this will turn the water green, and the plants and bacteria will be affected. I would recommend to isolate any diseases cardinals and treat them in a hospital tank with Furanace type of antibiotic.-Chuck>

Cardinal with blister/worm? -05/07/08 Hello WWM Crew! First, I have to thank you for the invaluable resource that you provide to all aquarists. Your website is brilliant: a veritable mine of information! That being said, I (of course) have a problem. <Thanks for the kind words.> One of my cardinal tetras has me stumped. At first, I thought he/she had mechanical damage from running into something in their habitat. Later, a sizable white spot developed inside of a large, clear blister. Additionally, on this individual only, a large swatch of black has developed beneath the eyes bilaterally, stretching from the mouth towards his/her gills. The black "stripe" lies beneath the iridescent blue scales that cover the cardinals body. For the time being (and since the "blister" started to develop some time ago) the cardinal is acting entirely normal, schooling with the 29 others, eating extremely well, full cardinal colour, no scratching or abnormal behaviour. A second cardinal has begun to show the lighter/clear patch of discolouration that preceded the "blister." <Ah, given the "syndrome" is spreading, I'm obviously thinking about Pleistophora as a possible cause. Whilst Cardinals do not seem quite as susceptible as Neons, they can still catch the so-called "Neon Tetra Disease". There's no known cure, beyond breaking the cycle of infection, which seems to be sick/dead fish releasing infective stages that get into healthy fish. Isolating symptomatic fish is the preferred first step.> Tank specs: ammonia, nitrite, 0. Nitrate, less than 5, more than 0. Soft water, pH 6.8, mixed treated tap and RO. Fluorite substrate, heavily planted. Tankmates: 30 cardinals (two symptomatic), four M. altispinosus (asymptomatic), one SAE (asymptomatic). The tank has been fully cycled for about 6 months (fishlessly, so much easier! Why doesn't everyone do it this way?). The tank is kept at 82 degrees F. Partial water changes are done at least weekly (often times more often 'there is still sediment on all of the plants from the Fluorite!) and the gravel is vacuumed each time (around the plants). <All sounds ideal for tetras.> I found a reference on WWM to worms growing in blisters on a Raphael Cat. Is this one and the same? <Blisters can of course be caused by a variety of things. People get blisters from things as diverse as badly fitting shoes and Bubonic plague. So one should be very careful about assigning causes to just one symptom of this type. What's more specific to Pleistophora is changes in colouration, loss of appetite, shyness, and then eventually death. Infected fish, particularly species other than Neons, can last for many weeks even months before death.> I found the reference here: http://www.wetwebmedia.com/FWSubWebindex/catfshdisfaqs.htm . However, the same individual got two different answers from two different experts (you guys really are): "This is likely some sort of "worm" parasite (more likely a digenean trematode/fluke but maybe a nematode)'¦ The Paragon might help... there are other vermicides... Levamisole, Fenbendazole, Piperazine... that might be tried" and "The blisters are really bacterial infections eating away the flesh of the fish. Treat with Nitrofuranace after you do a 30% water change and serviced the filter." <Blisters can indeed be caused by both these things. Unless you're a microbiologist, it is really impossible to know what the problem is. So the best you can do is run through the likely causes one at a time, trying different treatments.> There was also a reference to Dieter Untergasser's "Handbook of Fish Diseases": "There is one treatment method suggested in there that sounds like it should work (method C6)." I am afraid that I do not have this book, as I have never had any trouble with disease in any of my tanks (well, I rehomed African Cichlids for someone else that had been horribly abused, but that required nothing more than better husbandry and a larger tank). I checked local libraries with no success. I will purchase it now, but I'm afraid it will be a couple weeks to arrive. May I enquire as to this "method C6"? <No idea I'm afraid. In any case, with very small fish, the fish often doesn't last long enough for the treatment to work. It's simply a size issue. So while I'd certainly consider isolating and treating infected fish as best as I could, in this case if it *does* seem to be "catchy", I'd perhaps painlessly destroy both fish to stop the problem spreading.> If this is what is mal-affecting my cardinal(s), how should I treat? Should I treat everyone in situ or should I remove the affected individuals to the hospital tank? Do I need to tear down the tank to stop everyone getting infected if this is a parasite? Would they best be treated orally or as a bath? If I have to treat in situ, is there a medication that is plant safe, or do I have to remove the plants? I have attached a photograph of the cardinal (and learned that cardinals are camera shy, and move fast!) that shows the blister, white spot, and black under his/her eyes. I just noticed that the photo makes the cardinal look like it has Popeye, but I can assure you that it is only a trick of the light. <Isolate the infected fish for sure; perhaps maintain them for 2-3 weeks simply by providing good food and water and see what happens. Treat with an antibiotic or antibacterial if you want. It is possible the blister is nothing worse than a secondary infection caused by (for example) fighting. In this case, you should see some signs of improvement. But if the fish continue to deteriorate, get back in touch. At worst, you've isolated the potential source of infection and your other tetras should be fine. I have long since given up keeping Neons because of the plethora of mystery diseases they seem to come supplied with. Cardinals, though more expensive, are tougher and better value in my experience. But even so, you might be unlucky.> Sorry for the novel of an email, but I wanted to provide you with all of the information I could. Thank you for all of your help, and the excellent resource you have compiled for all of us (it is becoming harder and harder to resist that reef tank'¦). <So they tell me.> To you and yours, a wonderful day and weekend. Thanks, <Cheers, Neale.>
Re: FW Cardinal with blister/worm? 05/08/08 Hello Neale, Thank you for your advice on my cardinal issue. I have isolated him/her in a separate tank, and am working on catching the second. I hadn't even thought of NTD! Urg! The possibility didn't even cross my mind, since the fish is just as active as the rest of the school, and still the first to food. <Which all sounds positive, so fingers crossed the blisters heal by themselves.> There is also no white necrotic tissue present- only a clear blister (still with regular, bright colouration beneath, despite how the picture appears'¦), with an ich like spot inside. <Odd.> But...alarm bells ringing! When I took the cardinal out of the tank, I noticed that it does have a "lumpy" appearance. I hadn't noticed, because it is so subtle that you can't see it except when looking at the cardinal from above. <Well, keep an eye on things. Do provide the isolated fish with shade and good clean water so it isn't too unhappy.> As far as an anti-parasitic, do you have a recommendation that may work? <Wish there was. So far as I know, nothing works reliably, or even half the time.> I figure that if it is NTD, an anti-parasitic won't do any more harm. I would rather not sacrifice the fish if I do not have to, but in the event that they do begin to suffer, I will certainly break out the microscope. <I certainly hope the boffins at the "fish medication" labs come up with something for Pleistophora; it's a real plague and so depressing to watch. But breaking the cycle of infection/re-infection is essential, which is what you've done.> Thanks again, Tianna <Good luck, and keep us posted. Neale.> Re: Cardinal with blister/worm?  5/10/08 Hello again Neale, I hope you are enjoying your weekend! <Indeed I am! A lovely summery sort of day here in England.> I think the mystery of the white-sphere-filled-blisters on the cardinals has been solved. I went to perform a water change on the hospital tank, and ARGH! What appeared to be nematodes, of all different lengths, free swimming in the tank. The white spot (which, I guess, is a mass of subcutaneous parasites) in one of the cardinals had shrunk considerably. <Never seen this, or even heard of it. Sounds quite nasty. In any case, I'd immediately use some sort of antibacterial/antibiotic to prevent secondary infections caused by the burst cyst. An anti-helminth drug such as Prazi Pro should deal with the nematodes. But that said, most worms have complex life cycles that can't be completed under aquarium conditions (for example, they need to go through a bird or snail before they can back into a fish). So provided there were no secondary infections and the Cardinal otherwise recovers, I'd actually be cautiously optimistic.> This brings up another question that I will beg your help with. <Indeed?> Since removing the two symptomatic cardinals from the display tank, the "mystery illness" had gone wild. Nearly half of the cardinals are now showing symptoms. Clearly, there are nematodes in the tank that I can neither see, nor remove. Would it be more beneficial to just treat the entire display tank, and stop torturing the poor fish in a "naked", uncycled hospital tank (especially if there are parasites living in the display that will simply reinfect the fish again)? <In an uncycled tank, you can use Zeolite to remove the ammonia directly, and that's cost effective and reliable with very small fish like Cardinals.> As my hospital tank is only 10 gal, I cannot realistically move all 30 cardinals plus the other inhabitants to tear down the display to disinfect. I could be wrong, but I think this would do more harm than good. <Agreed.> Before the "big break" in this mystery, I had purchased some of Seachem's Cupramine as a shot in the dark. Would this be effective against the subcutaneous nematodes, or would I be better served by exchanging it for something like Praziquantel (if I can find it)? <Cupramine is certainly worth a shot before trying anything else.> I always quarantine new livestock, so seeing this now, after several months in the tank and having been quarantined for a month prior to moving to this display is mind numbing. I guess nothing is fool-proof! <Quite. As I say, this disease is something I've never encountered. Possibly Bob Fenner can offer more advice.><<Sorry to say, RMF is out traveling and without sufficient internet access. -S.M.>> Thank you so very much for all of your help (both on this mystery, and the rest of this website!) <We appreciate your kind words.> Have a great weekend, Tianna <Enjoy your weekend, too. Cheers, Neale.>
Treating Discus with Ich - 8/14/07 Hi Crew, <Hi Greg, Pufferpunk here> I apologise for the long email up front. <It's ok, we need to know what's going on & how you've been treating.> I am having a bit of a problem getting rid of White Spot (Ich) from my well planted low-tech 6x2x2 Discus & community aquarium. The tank has been up and running for seven months and was fully cycled after three months. From day 1 the temp was set at 30C (approx 86F) and I didn't have any problems at all with disease etc, but Ich must have been in the tank somewhere as when I recently lowered the temp down to 28C (approx 82F) to help the plants grow I suddenly had an outbreak of Ich that I am having problems getting rid of it. <That's your problem right there. Discus' immune systems are compromised at lower temps. Never mind the fact that ich dies off mush faster at higher temps (86-88 F).> So far I've had four 'attacks' against the Ich as follows: 1st Attack - I used 'Rapid Ich Remedy' which contained Formalin and Malachite Green, followed instructions as per the bottle (5mL per 20L = approx 150mL per dose) on days 1, 4 and 7 which cleared the Ich for about a week, then it came back. 2nd Attack - I again used 'Rapid Ich Remedy' following instructions as per the bottle (5mL per 20L = approx 150mL per dose) in terms of dose rate but I dosed on days 1, 4, 7, 10 and 13 which again cleared the Ich for about a week, then it came back. 3rd Attack - I used Waterlife's 'Protozin' (the double strength version) which I assume also contains Formalin and Malachite green as it looks & smells the same as the 'Rapid Ich Remedy' medication, followed instructions on the bottle (2.5mL per 75L = approx 25mL per dose) on days 1, 2, 3 and 6. This again cleared the Ich for about a week, then it came back yet again. 4th Attack (currently I'm on day 4 of this 'attack' & I'm getting desperate)... I'm again using Waterlife's 'Protozin' in combination with an Anti-Parasite medication for fish ponds (made by Interpet) which contains Formalin. I'm dosing as follows (don't freak out): A 13 day attack plan, where I'm dosing the Pond Anti-Parasite medication (25mL per 1,100L = approx 15mL per dose) on days 1,2,3,4,5,6 and 7 at 7:00AM and I'm also dosing Protozin (2.5mL per 75L = approx 25mLs per dose) on days 1,2,3,4,5,7,9,11 and 13 at 7:00PM i.e. each medication for the first 7 days is 12 hours apart. Note: I'm not performing any water changes during treatment but I usually change 20% of the water twice per week. Bad idea! Discus need 90% weekly water changes. During ich outbreaks, 80% every other day is necessary to remove the free-swimming parasite from the water column. It shouldn't be necessary to treat ich with any meds at all. High temps & 2tbsp salt/10gallong should be sufficient, along with large bi-daily water changes. Using all those different meds are just making the ich stronger & the discus weaker.> I figure the 4th attack will either kill the Ich, and/or kill (and probably permanently preserve) the fish with all that formaldehyde, or perhaps the Ich and the Fish will survive and I'll likely give up and accept that I am stuck with Ich for the rest of this tanks life. I guess I could get rid of all the plants and fish except the Discus and then raise the temp up to 31 or 32 degrees C (approx 89F), as I figure the Ich will not cause too many problems at this temp for Discus. However I really don't want to go back to running my tank above 30 degrees C (approx 86F) as the plants (mostly Amazon swords, Ambulia and Water Sprite) don't like the higher temps at all, as everything looks and grows much better at 28C. I really like having a planted Discus aquarium and since all the fish get along so well its a shame to have to give into this single celled monster! <I have a fully planted discus tank. I don't use any of the plants you have listed. All my plants are also low-light species. Right now, I have many species of Crypts, Anubias, Java fern & Crinum. See: http://www.aquariumplants.com/Warm_Water_Discus_Plants_s/20.htm Many plants require CO2 supplementation (which I don't use). In addition, I add Yamato Green weekly (www.yamatogreen.com) & poke Jobe's Spikes under their roots, every 6 months.> Now you may be wondering how everything has held up through these multiple attacks against the Ich? Well during all the treatments so far I have not noticed any effect whatsoever on my biological filtration (no measurable NH3 or NO2) but then again the plants may well be taking care of NH3, NO2 and NO3 as they are still growing just fine through all of this. <Anti-parasitic meds do not harm biological filtration.><<Mmm, I would NOT make this statement. Many compounds sold as such definitely WILL affect, stall nitrification... directly and/or indirectly. RMF>> Even all the fish (including the supposedly fragile Cardinal & Rummy Nose Tetras) don't even seem to notice that they are being medicated at all, which makes me wonder if the medications are being negated by the plants or perhaps by something else? Like I said my 4th attack is quite brutal and I'm likely to suffer losses but I'm prepared to do almost anything to get rid of this stubborn Ich once and for all. Maybe I need to increase the dose rate? Maybe I need to try NaCl and raise the temp? <Now you're thinking in the right direction!> I have an 80L quarantine tank that I use for all new fish but it is not big enough to move all the fish in there for separate treatment. The QT is usually set at 30C and all fish that go through it get nuked by Multi-Cure (basically Methylene Blue, Malachite Green and Formalin) and then I watch them for a minimum of two weeks (total of a 3 week stay in QT) before fish are transferred into the main 6x2x2 display tank. I've never lost any fish apart from the odd Cardinal or Rummy nose using this method but I find them rather delicate at the best of times when purchased from the LFS - they always look starved! In case you need to know the tank is setup as follows: 6x2x2 glass aquarium with approx 600L of water 1x Eheim 2228 canister filter 1x Aqua One 2450 canister filter (UV-C is off during treatment) 1x air stone running 24/7 Temp at 28C (approx 82-83F) pH = 7.4 Hard tap water (treated with a double dose of Prime during each WC) 10 healthy young Discus (see attached photos) 5 Black Neon Tetras 12 Cardinal Tetras 15 Rummy Nose Tetras 5 SAEs 3 BNs 2 Sterbai Cory Catfish 4 Kuhlii Loaches Well planted (actually the plants are growing really well even throughout the treatment - see attached photos taken 3 days ago for reference) <Sounds/looks like a lovely tank! Lighting?> Any suggestions on what I'm doing wrong or what I can do to win this battle would be appreciated... thanks Crew! <Try my suggestions above. The plants may not be strong enough at this point to handle the treatment but I think the fish are worth the risk. ~PP> Regards, Greg Simpson Perth, Western Australia

Re: Treating Discus with Ich (or Neons in this case)... actually Cardinals...  Poor Advice... 8/15/07 Thanks for your quick reply Pufferpunk! <Sure!> It's actually not the Discus that seem to be effected by the Ich, it's the Cardinals! <That's what I get for assuming...> After a few weeks it's like they are slowly being sprinkled with salt and they 'flick' against the stems of plants (classic Ich symptoms in my opinion). I guess the poor Cardinals are feeling poorly from the anti-parasite medications and thus cannot resist the Ich as much as the stronger fish. <Yes, I believe so many meds will actually weaken the fish's immune system.> What about Copper based treatments? I hear copper can be quite effective too. <Copper is very effective but extremely dangerous, especially on weakened fish or used incorrectly. You could try a saltwater dip on them but they are so tiny!><<RMF would NOT SW dip small S. American Characins>> I guess after round 4 of my 'attacks' I'll try the higher temp & salt combination as round 5. <I think this is your best bet. Don't forget to do huge water changes every other day, trying to clean the substrate (as best you can with the plants), to remove the free-swimming parasites.> If that fails Copper based meds might be round 6. I hope this does not turn out to be a 12 round fight! I've kept tropical fish for 24 years and have never had such an issue with disease as I have this time around. I've had Ich before in smaller/less planted tanks and usually after a basic Ich treatment it's resolved for good. I must have a bad/resistant strain of it!!!! <Add Melafix to heal the wounds from the parasite boring into the fish. Good luck, let me know how it goes. I'm sure there is tons of info on ich treatment at WWM. You can also read this: http://www.thepufferforum.com/forum/library/hospital/fwich/ ~PP><<This citation has NOTHING to do w/ FW ich treatment... RMF>> Regards, Greg


I am obsessed with keeping freshwater cardinals! I just can't keep them alive!   5/13/07 Hi! <Hello!> Hope all is well with you.  I have a question I hope you can help me with. I have had reef and saltwater tanks for a couple of decades, and I do pretty well. I even have a 600 gallon one in my kitchen wall! <Sounds nice. Though if you prepare sushi in the kitchen, I imagine the fish get rather nervous wondering if they're next...> But I am obsessed with keeping freshwater cardinals! I just can't keep them alive! <I we talking those neon tetra look-alikes, Cheirodon axelrodi, or the freshwater examples of the marine cardinals such as Glossamia aprion, the "mouth almighty"? I assume the tetras.> I have a 45 gallon tank with a sump. (an old reef tank). I had it setup with a BioWheel, and gravel on the bottom. I suctioned the gravel monthly, did a 33% water change monthly, and no luck with the cardinals. <Cardinal tetras can be tricky for a variety of reasons, but once settled in they're basically tough little fish. The main problem in my experience is Neon Tetra Disease (NTD), which works its way through cardinal tetras at about 50% mortality, i.e., if you buy 20 cardinals, and you get the dreaded NTD, you can lose up to half of them. Better than Neons, where you lose all of them, but still annoying. Another issue with cardinals is they are all wild-caught. In fact, they're the most numerous exported tropical fish from South America. Anyway, by the time they reach the market countries around the world, they might not have eaten for weeks. My guess is that healthy, well-fed cardinals are more or less NTD resistant, but when weakened and cooped up in a retailer's aquarium, they are far more susceptible to this disease. So as with any wild-caught fish, buying when a new batch arrives can make sense, and then quarantining and feeding on a variety of live/frozen foods makes all the difference.> I then added an undergravel filter (I know....dumb idea, but I was desperate!) <There's nothing intrinsically wrong with UG filters. They do a good job of maintaining water quality. The problem with UG filters is their incompatibility with aquascaping and rooted species of plants more than anything else.> No luck. Nitrates off the chart. Dead cardinals. <Odd, given how small cardinals are. They don't eat much (and don't need to eat much, either). They're classic "pinch of flake a day" fish in my book. When you say "off the scale" you mean above 100 mg/l? What is the nitrate level of the water out the tap/faucet? I have to confess to keeping mine in rainwater with a bit of tapwater added. Seems to work well.> Someone suggested bioballs.  Would not that make the nitrates even higher? <Worth trying I suppose but I don't find nitrate removal systems in freshwater tanks to be of much value. Freshwater fish don't care that much provided the rise in nitrates is slow, and even between 50-100 mg/l you shouldn't get mass die-offs of fish except with certain species (Tanganyikans for example). Simple water changes are, IMO, a better approach to nitrate management, and the filter is best devoted to biological filtration, i.e., ammonia/nitrite management rather than nitrate.> I have used Amazon rain additive (is that stuff any good?) <Not really. Looks nice, but doesn't really do anything if you have hard, alkaline water. In softer water, may help acidify the water a little, but approach the concept of acidifying water with caution, as it's easy to mess up.> No luck. PLEASE do you have an ideas?  Thanks! <Have a read of this: http://www.wetwebmedia.com/ca/volume_2/cav2i3/cardinal_tetras/Cardinal_Tetras.htm for some more ideas.> Ron <Cheers, Neale>

Hey Bob, Tetra sizes  3/9/07 Hiva, I was looking through some pics on WWM and noticed this page http://www.wetwebmedia.com/FWSubWebIndex/tetragonopterinae.htm, specifically the cardinal tetras listed at length 2.5 cm/2 inches <Mmm, one> ...these are not equal measurements....and Neons lists at 2.2cm...that's not quite an inch...seems quite small to me? <Yes... I just looked... lifted these from fishbase.org... though I swear I've seen bigger. BobF>

Neons vs. cardinals 7/21/05 Hello, wondering if I could get an opinion on these tetras. I'm planning on a 108 gal. community and want to have either neon tetras or cardinals as the main schooling species. What would be your recommendation with these fish for overall color, adaptability with other community fish and most of all hardiness? I know both require the same water conditions. That's it. Neons or cardinals? Appreciate any input on this subject?..........Regards, Craig P. <Mmm, am a big fan of both species, but will side with the Cardinals... for bigger size, greater longevity, relative hardiness. Bob Fenner>

Re: Neons vs. cardinals 7/22/05 Mr. Fenner thanks for your response and the cardinals sound good to me as well. I received a response from you on the Hagen lights for my tank last week; again Ty. I realized that your name was familiar and dug up one of my FAMA magazines from years past and found your article. Showed the e-mail I sent you to my son and then your picture and he was really impressed!! "Dad he's an expert", <Heeee!> were his words. He's 11. I've been in the hobby for about 10 years now and still enjoy it very much...... just ask my wife, lol. It's good to know expert advice is a click away.......... Thanks again. I live in the province of Newfoundland Canada and the hobby has really taken off here this past few years; both fresh and saltwater, but I find staff with any knowledge are few and far between. Anyway, I had to drop you this note to let you know, it's great to get advice from the "expert"..................... much regards.....Craig P. <Hmm, whenever I hear the term, I always think of "ex spurt"... as previously married and flow under pressure... Thank you, Bob Fenner>

Cardinal problem Date: Sun, 13 Mar 2005 Hey there, I was wondering if you'd be able to help me with something. I have had FW tanks for a long time but have not had any real luck with setting up a school of either Neons or cardinals. My current "failure" is a discus planted tank. It is a 46 gallon bowfront tank with 6 discus and 3 clown loaches. <Too crowded... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/discusfish.htm > The water conditions are NO3 is 20ppm, NO2 is 0, hardness is 120, alkalinity is close to 0 and pH of 6.4ish. Temp is 85F. The discus are doing fine and I do daily water changes of 5-10 gallons using RO water mixed with 1/2 gallon of regular non-RO water (for the plants).  <Good practice!> Discus show no signs of stress and live normally. I brought home 11 cardinals about a week ago which I bought at a LFS. They all seemed fairly ok even though a lot of them had skinny stomachs (due to lack of food I'd guess). <Yes, common> I first placed them in a quarantine tank, losing about 4 in a few days. After 5 days, and the rest of the cardinals looking ok, I moved them to my discus tank hoping for some survival. few days later, I am looking at 3 fish left (which do eat) but are covered in ich. <Yikes... should keep quarantined... for a few weeks> none of the other fish show any kind of ich or other diseases. The temp is high (for discus) and I was thinking ICH wouldn't live, but these cardinals are covered. <Likely will die there> I am at a loss here. Please help if you can see what I am doing wrong. Thanks, DK (P.S. I'd even go to Neons if that meant they would live better, but I read somewhere that cardinals take the high temp better.) <This is correct... I would try again, with a new batch of Cardinals.... but quarantine them longer... slowly raise the water temperature (am sure the store did not have them in the 80's F) to the Discus water conditions, fatten them up first. Bob Fenner> 

Going To School Will cardinal tetras school with neon tetras?  What other types of tetras will school with Neons? <Well- as far as schooling "with" the Neons, any tetras of similar size could join up. However, I have seen Neons school with Cardinal Tetras, Glowlight Tetras, and even Rasboras on a few occasions, so anything is possible. Usually, in my experience, anyways, the Neons seem to school with Neons, Glowlights with Glowlights, etc. Keep an eye on these little guys- their behavior is very interesting! Enjoy! Scott F.>

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