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FAQs on  Corydoras Cat Parasitic Disease

FAQs on: Corydoras Catfish Health 1, Cory Disease 2, Cory Disease 3, Cory Disease 4
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: Environmental, Nutritional (e.g. HLLE), Social, Infectious (Virus, Bacterial, Fungal), Genetic, Treatments,
Related Articles: Callichthyid CatfishesSummer loving: cats in the garden, kittens in the kitchen by Neale Monks,

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


Costia on Bandit Cory(s), invert safe treatments?          5/27/15
Hi, I have a planted 65 gal tank 4 years+ running with honey gouramis, kuhli loaches, Hengle's Rasboras, bandit Cory's, Amano shrimp, Nerite snails, Oto cats. I think the Oto cats brought in disease and I had some loses of livestock and then things seemed to stabilize with no more dying fish. Some of the Cory cats, one in particular, have gray slime on them that seems to be 'Costia'.
<Costia, now called Ichthyobodo, is an awkward parasite for sure. It's one of the causes of Slime Disease, though not the only one, so do be aware of that. Curiously, but significantly, Costia is harmlessly present in most tanks, and only becomes problematic when the fish become stressed. So it's important to try and think of why that might be the case. In any case, there are various proprietary treatments out there, such as eSHa 2000 (no formalin or copper), QuickCure (has formalin in it though) and Interpet Anti Slime and Velvet (this latter also contains formalin). Otherwise, apart from formalin (which does indeed work well against Costia) any metrifonate-based medication should work well.>
I have gradually turned the heat up from 77 F to 83 F. The slime seems less on the worst Cory but still there. I can't net them out of the tank, too many obstacles. The invertebrates make using most of the medications recommended for Costia not safe to use.
<Indeed. Anything with copper or formalin in it may be toxic to shrimps, snails, and potentially sensitive fish including loaches and catfish. So you've got problems.>
Is there anything else that I can/should be doing? Does Paraguard have any effect on Costia?
<Paraguard has a chemical similar to formaldehyde in it, so wouldn't be an obvious choice for use with your community of species.>
Prazi-pro did not help at all.
<Obviously not. It's a dewormer.>
<Cheers, Neale.>
Re: Costia on Bandit Cory(s), invert safe treatments?      5/28/15

I'm not sure if I can get eSHa 2000 here in Canada. I'll look around.
<Or order online, via eBay, etc.>
The inverts in this tank have been through Paraguard treatment before without losses. I've never had it obviously cure anything, but if you think it would have a chance at Costia I'm willing to try it. I have a bottle handy. Should I adjust the dose for the Cory cats or Otto's?
<Adjusting doses down is fairly pointless. Generally the dose stated on the bottle is the dose needed to kill the parasite. Half doses might work, but then again, they might not. You could consult with the manufacturer for
guidance. SeaChem do have an FAQ, here:
They don't sell this product as "reef safe" as you can see, which means it might be toxic to invertebrates... but then again, it might not! That's probably about as sure a reply as you're going to get on this product.
Cheers, Neale.>
Re: Costia on Bandit Cory(s), invert safe treatments?      5/29/15

I tried the Prazi-pro first because I thought it might be skin flukes. I'll try the Paraguard after I do a water change on the weekend and see if that helps. If I go much higher with the water temps I am going to lose some plants.
I'll let you know if it seems to do anything.
Thanks, Jeff
<You're welcome, Neale.>

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

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

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

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

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

Cory problem I have 37 gallon community tank set up that is just getting back to full speed after a store whose name I won't mention, but whose initials are WM. sold me a Pleco with a virulent case of Ich that was not obvious when I purchased him. <Happens... all the time> Despite aggressive treatment, I lost all my fish (some of which I had had for years) except for 4 rosy barbs (tough little suckers) most on a horrific night where I lost one an hour. Anyway, I do have a point. Over the last 3 months, I have been adding back fish mostly tiger barbs (9 of them now) from a reputable LFS. I recently added two green Cory cats, but noticed that one of them has what appears to be tumors. Two on it's side and one on it's tail. The ones on the side appear to be under the scales or the same color as the scales. All are rather perfectly round and small about the size of a bb. Do you have any idea what this could be, how I can treat it and if it is contagious? Any help would be appreciated. I don't want a repeat of what happened a few months ago. Thanks so much. You guys have always been a great help! <I do have a pretty strong suspicion re the identification of these spots... they're either encysted worms (likely nematodes) or Microsporideans... either way not really treatable nor catching. No problem. Glad to see/state that you stayed in the hobby. Bob Fenner>

Treating Corydoras paleatus in main tank 8/24/05 Hi again, I have a question about treating my main tank for Ich. I have a 10 gallon tank with 4 peppered Corys in it right now. I've recently moved my 3 goldfish into another 10 gallon tank and don't know if I want to keep it as a QT tank or keep them in there for good. <... you were keeping Callichthyid (tropical) catfish with coldwater goldfish?> I also moved my 4th goldfish into a temporary 3? gallon tank. I plan on either giving that one away to a friend or a pet store because it's getting way too big and it's pretty aggressive towards one of my goldfish. I know... too many goldfish for a 10 gallon tank haha <Ahh, not funny...> I didn't know/read about fish when I got them for my birthday so here I am with too many. <Very common> Now I'm trying to get rid of them. Anyways the goldfishes are being treated for Ich in the other tank right now but I don't know what to do about the Ich that could be in my main tank and my Corys. I want to just treat them in the main tank but I heard Ich med kills the beneficial bacteria. <Likely so> I wanted to try treating the tank with salt but I don't know how well my Corys would do in it. <Don't like> Is there a way to treat my main tank with my Corys still in it without the risk of any dying? <Half dose/s, elevated temperature> They are doing really well and I don't want to jeopardize their lives. And does salt kill the beneficial bacteria? <Yes, can> Whenever I treat fish in a QT tank they always seem to get so sluggish and I don't know if I'm doing it right or not. <Good question, speculation> Oh and one more thing! This is just for the future if I wanted to keep other fish. I want to add 2 more Corys to the 4 that are already in the tank. Will any kind do or should I stick with peppered Corys? <Can mix> I would also like to add a few fish that aren't bottom feeders. Which kind would do well with Corys and also won't make my tank overstocked? Thank you so much your help. It's great to know that I have a reliable source to direct my questions to! Wayne <Read on my young friend... re livestock selection, Ich... the latter here: http://www.wetwebmedia.com/FWSubWebIndex/fwich.htm and the linked files above. Bob Fenner>

Wormlike parasite 5/30/07 Hello there, <Good morning> I have a problem with two Bronze Catfish, they seem to have a parasite that I can't identify. One of the Bronze Cats is new, I've had it for a few days. My tanks isn't very old (less than two months, but I have been monitoring it closely and it has cycled). It is a 90 litre tank (24 ish gallons). Currently my temp is 79, pH is 6.8 , ammonia 0, nitrites 0 (I only tested for nitrates once about three weeks ago and there were none, the tank is quite heavily planted so I'm guessing whatever nitrates have been produced are being used up or removed during water changes). I don't think that water quality is affecting the fish, but nevertheless the Bronze Cats seem to have extremely tiny, whitish, wormy looking things attached to the very ends of their fins, they are difficult to see with the naked eye. There don't seem to be any on their bodies, they just seem to be on the ends of the fins, hanging like little tassels that move when the fish are swimming. They are very small, they must be less than a mm long. There seem to be more on the newest Bronze Cat, but I believe that the other bronze has caught them now too because I noticed a few today ( I'm afraid that they are spreading). I have 2 Pepper Cats and two Sterbai Cats and they seem unaffected, none of the other fish in the tank seem affected either (Neons, Gouramis, SAE etc.). These parasites don't seem to be bothering the fish so far (no clamped fins, scratching or heavy breathing) but I know that this could change. These two Bronze Cats also seem to each have another problem as well ( I know this is getting boring but I think it's better to get all the details out in the open). My older Bronze Cat is a long finned variety, very pretty, but I think that someone likes the look of his magnificent dorsal fin because sometimes it suddenly looks munched or shredded. It heals readily and does not seem to get infected so I don't think that it's fin rot. I don't keep any 'aggressive' fish in my tank, but maybe a naughty baby Clown Loach might have nipped him? ( Who knows what any of the fish get up to when the lights are off?). The newer Bronze seems to have lost the barbels on one side of his mouth, it doesn't look infected. This seems to have happened quite suddenly as well ( it was while I was inspecting this that I noticed the parasites). I think that the barbel may have been damaged during feeding. I try to break up a few small sinking wafers for all my bottom feeders to have an even chance but I have still noticed that the Clown Loaches are pretty dominating at feeding time. My Betta also gets quite aggressive as well. Could the barbels have been severed during a feeding frenzy? I realise that the parasite and the injuries may be related because the fish may be more susceptible to infection if they're injured. But do you have any idea what the parasites are and how to treat them? <Mmm, microscopic examination would be the route to go here, but likely some type of Fluke (Trematode)> My other issue is with a new Blue Ram. I bought a male and a female (they get along well) and it is the female who is looking rough. She has got small white patches on her body and fins. They aren't Ich spots but they don't look cottony or fluffy either. Could they be a fungus infection that is just starting out? Or is it bacterial? <Impossible to state for sure... but the fish being new, I would be very conservative here re treatment> I don't know what to treat with. I have a malachite green/Methylene blue/quinine solution which is meant to be a sort of 'cure all' tonic, <The Malachite is quite toxic... I would hold off for now> but I am afraid to use it with the Clown Loaches being in the tank now, and I don't want to destroy my biological filtration either. Would the medicine that I have be suitable to treat the worm parasites and the fungus or would you recommend something else? Should I treat the whole tank? ( I don't have a QT but could do a short soak in a bucket?) Sorry this is so long but I would really appreciate any advice you could offer. Kind regards, Jessica in New Zealand <I would treat the worm problem with an Anthelminthic (likely Flubenol or Prazi(quantel)... covered on WWM (see the indices, search tool)... and the current problem with the Ram... not at all, other than maintaining good (soft, acidic, warm) water quality. Bob Fenner>
Re: wormlike parasite continued 5/31/07
Hi WWM, <Jessica> Thank you Bob for your reply regarding my unidentified 'worms'. Before receiving your reply I went to my LFS to buys some plants and asked them about the worms. The parasite description stumped the staff there but one of them eventually decided that I should try Praziquantel. He said it was what they used to treat parasites on their discus so we figured it was worth a go. <Yes> I bought some of the Praziquantel but I waited to hear what your suggestions would be (no offense to my LFS, just thought you guys would have had more experience with parasite ID's). Imagine how great it was to hear two different sources suggest the same treatment! I used the Praziquantel this morning (on the whole tank as I believe it was spreading to all my catfish) and it looks like the parasites have already come off the fish's fins. I can't see them anymore. So I'm guessing that the Praziquantel made the parasite fall off of their hosts? <Very possibly> I was given two doses and told to use the second one in a week's time, would you recommend this and should I do my usual weekly water change (about 15-20%) beforehand? <I do recommend both> I also wondered if I could use some MelaFix to help my Blue Ram? <Mmm... not really worthwhile> Whatever is ailing her seems to be getting worse, I'm still not sure if it's a bacteria or a fungus. <Likely water quality...> She just seems to have small, white clumps on her body and fins (they are different to the parasite that was on my catfish), some of them are looking a bit stringier (still not cottony/fluffy though) than they did before so maybe this is a fungus? <Do see Google re Lymphocystis... pix...> She's also looking a bit more 'clamped' than she was before, still feeding and reasonably active though. Her partner looks fantastic and they seem happy together, he is not beating her up and neither is anyone else. Maybe the male was a bit aggressive in the bag on the way home from the store (although it wasn't a long trip and I didn't see anything amiss), or maybe she was already sick at the store. The stock there all looked pretty good and my water chemistry seems suited to their requirements. I'm not sure what's making her sick, but I'm worried that she's getting worse and maybe the MelaFix would be a milder course of action (rather than the malachite/Methylene/quinine tonic that I have). <Neither one is suggested> I'm aware that the MelaFix may not have an effect on whatever is making her sick, but I just thought it would be worth a try if it was safe to mix with the Praziquantel. I've done a ton of research on both of these today, but I haven't seen anything saying whether you could mix them or not. At least now I know more about them on their own :-) <Can be mixed... but the "Fix" product is just a "tea"... soaked Melaleuca leaves... at best it might lower the pH here> A third and completely unrelated question is that I have two Honey Dwarf Gouramis (Trichogaster chuna), a male and a female. <Ahh! One of my favorite species> They seem to get along apart from the odd brief chase here and there, which I'm sure is natural. Today (before dosing the Praziquantel) I noticed that the male has darkened up considerably on his ventral area. It is a section that runs from under his mouth and eyes, just under his pectoral fins, along past his bottom and into his fins (anal fin? pelvic fin?). It's actually quite a defined, diagonal line. The colour seems to be a mottled black pigmentation and it extends around his belly. I've seen him blow a few bubbles at the surface, but no bubble nest building. Is he trying to impress his lady friend? Or could this be a sign of something else? <Likely is reproductive/stress color change...> Again, thank you for your time. I'm glad that there are credible websites like yours for people to turn to with their queries. Jessica <Welcome my friend. BobF>

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