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FAQs on  Corydoras Cat Disease Diagnosis

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

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

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

 

Hopefully final update on Blobby White Panda Corydoras     11/30/17
Hi Crew, back in October I wrote to you about some sick Corydoras I had in quarantine that had developed a white coating and we had a bit of to and fro on different treatments, whether to euthanise etc. Despite trying every treatment available to me I have slowly lost more and more of the Corydoras including one that didn't have any of the white patches, but whose mouth seemed to have become swollen shut by small warty or tumorous bumps.
Tonight I finally lost the last of the white bumped corys.
<Sorry to hear this.>
I still have 3 Panda Corydoras that are mostly clear, one has a white lesion on his tail which hasn't changed for weeks, the others look a bit odd around the nostrils or on their fins but seem fairly healthy.
<Understood. Would continue to keep these isolated for now.>
The 2 sterbai Corydoras that were in the same quarantine tank never showed any sign of this illness, and neither have the rasboras that are also quarantined in this tank.
<Odd, but I suppose a silver lining.>
To recap: samples I have tried to take of this white matter have resulted in scraping off a waxy substance with no details of note when viewed under the microscope.
<May simply be mucous and/or decomposing tissue, neither of which will show much under the light microscope at low powers.>
Affected fish look really terrible but have mostly had an active demeanour, eating and swimming fairly normally right up until the day they die.
With this last fish I caught him in his death throes (laying on his side and struggling to swim or orient) and decided to euthanise him since his condition was so poor and I did not expect him to get better. After netting him out he appeared to have a red lump, an abscess or tumor I guess, on his caudal peduncle which looked to have broken to the surface and might be what finally did him in.
<Agreed.>
Since, unlike the others, he had very thick bumps with strips of healthy skin in between, I became determined to try and get a good sample off him to have one last look under the microscope. Upon closer examination I saw two tiny blisters on his white bumps, which finally clued me in that these bumps are not ON the skin, they are IN the skin. Or, rather, maybe they are the skin, thickened?
<Could be either really, and without seeing the fish, impossible for me to say. The fact is that many skin infections do cause blisters just below the surface, e.g., Whitespot cysts. So in and of itself, the fact there's a thin layer of skin over a growth or cyst doesn't rule out external parasites or infections.>
The stickiness I experienced when trying to take previous samples would have just been slime coat. I tried to scrape the thickest white patch and it was much like when your hands are wet for too long and the thickest parts swell and become easily damaged.
<Understood.>
With this new information I Googled once more and almost immediately came across a page about Carp Pox (Cyprinid Herpesvirus)
https://www.koi-pond-guide.com/carp-pox.html and the picture on this site looks pretty close to the blobby lumps that
were covering my Corydoras. The description of waxy lesions and fish that remain active and with a good appetite also matched what I experienced with my fish. I don't know if corys are susceptible to this particular virus but it does seem they had something similar all along which would explain why none of the treatments I tried worked. The page lists Lymphocystis and epitheliocystis as other possibilities but none of the pictures I saw of those looked anything like what was on my corys (and I suspect the antibiotics would have treated one of those).
<Viral infections are very difficult to diagnose except perhaps in those cases, like Carp Pox, that the symptoms are well defined and familiar enough that aquarists can recognise them easily enough.>
Have you heard of Corydoras being affected by a fish herpesvirus before?
<No; it's generally regarded as quite species specific, affecting Koi, its Common Carp ancestor, Goldfish, and its closely relative the Crucian Carp.>
I do remember our government in Australia talking about releasing CHV-3 into our waterways to kill pest carp species which makes me think they are sure it doesn't cross to other species.
<Indeed; what experimental evidence I could find on this suggests that native catfish, eels, and Rainbowfish, among others, were all unaffected by the virus.>
Mistakes have been made before though - cane toads spring to mind. I can't find much more information out myself but I feel that I have finally got a satisfactory idea of what was going on. I have been pretty strict with not sharing equipment between this tank and my other tanks and now I'm wondering if the usual net-disinfectant etc and washing my hands, will be enough to prevent the spread of this virus. Any advice on this front would be appreciated!
<CSIRO feel that the virus is not going to risk Australian native fish, though that's primarily because there are no native cyprinids in Australia, so even if the virus adapted a little bit, there are simply no even halfway related carp-like fish in Australia it could mutate towards. Catfish are far too distantly related for this risk to be significant. It's a bit like how humans can get mutated versions of viruses that originally infect monkeys or apes, but generally don't get viruses that infect cats or horses.>
Anyway just thought I would pass on my findings and my suspicions that this case was some kind of viral skin infection. Perhaps in healthier or hardier fish it even may not have been fatal as it took 8 and 9 weeks to kill four
of my Corydoras. So for now I will continue to monitor this tank and keep everything isolated as before and I will continue with just clean water and good diet as the treatment.
<Indeed. Just because CHV isn't the issue here, doesn't mean a virus of some kind can't be in play. There absolutely are viruses that affect widely disparate species out there -- the DGIV virus that affects Dwarf Gouramis has also been detected in certain other species. How common this is, and how dangerous, is hard to say. One issue is that there really are so many viruses out there -- and as aquarists we can diagnose so few of them -- there almost certainly is a Corydoras virus out and about, we just don't recognise it.>
Thanks for your help!
Bronwen
<Welcome. I'd tend to put down your experiences to bad luck. Might be a virus, might not. Hard to know. I'd isolate the sickly ones for another couple weeks at least, but if the disease has otherwise 'run its course' it may have run out of species it can infect. The Rasboras can probably go into the display tank, and the Corydoras sterbai may as well, since they seem to be immune or at least not affected by the virus, bacteria or pathogen. Good luck! Neale.>

Peppered Cory Illness      7/1/16
<Am responding here for timeliness-sake, but asking Neale Monks to respond as well>
Hello, I have been assisted by your staff in the past for some issues with angelfish, so I thought I might get some help with my Corys. I have the following setup:
55 Gallon
Artificial Plants
Driftwood
Sand substrate
Fluval 305 Canister Filter
5 Corys (3 Peppered and 2 Green)
5 Neon Tetras
5 BN Plecos
4 Silver Dollars
1 Male Betta
Food: Crisps, algae wafers (veggie and protein) daily. Betta gets a small amount of "Betta Food Pellets". Weekly offerings are bloodworms and/or Tubifex worms. Plecos LOVE cucumbers and the silver dollars enjoy romaine lettuce leaves.
I do 50% water changes every week and clean my canister filter every 2 weeks (suggested is once a month but I do tend to overfeed with the silver dollars). Two of my peppered Corys are ill. Both have turned a dark, almost, black. Listless, no eating.
<Mmm; something environmental at play here... introduction of a pollutant?

With the lettuce perhaps... I take it the insect larva and worms you're feeding are processed... Not live>
The larger of the two (female) is at least 3" long and she's just over 6 years old. The smaller (male) is about a year old and he is the same. The female has ragged fins and the male has a "scrape" on one side of the his tail where the paler "flesh" is showing and for a day or two had a red ring around the lower half of his eye orbit.
<Physical trauma? From... the Dollars? The Plecos?>
That has disappeared. The only outward sign of illness I have noticed is the female had an episode of her chronic swim bladder disease. From time to time (every 6-8 months), she will float to the water's surface and end up laying on her side for part of the day. I always withhold food and within 8 hours, she's great again. This happened last week. I was unable
to do my regular weekly water change last Saturday, because I had the flu.
So, my parameters are as follows:
pH 7.5
Nitrate: 5
Nitrite: 0
Ammonia: 0
<Water temp.?>

The female is my favorite fish. She's typically happy and LOVES water changes. She is just listless and I think she may have a little spot on her forehead, but I really can't tell with the dark color. I would sincerely appreciate any advice you can offer. All the other fish in the tank are happy and acting normally. I do notice some dark-looking (dark brown) algae or slime just beginning to form on my plastic plants, but this is something that I get regularly and clean each week.....
Thanks!
PS - Going to attempt to get a couple of pics to send as well
<Good>
Kristi A. Jones
<Bob Fenner>
Peppered Cory Illness /Neale      7/1/16

Hello, I have been assisted by your staff in the past for some issues with angelfish, so I thought I might get some help with my Corys. I have the following setup:
55 Gallon
Artificial Plants
Driftwood
Sand substrate
Fluval 305 Canister Filter
5 Corys (3 Peppered and 2 Green)
5 Neon Tetras
5 BN Plecos
4 Silver Dollars
1 Male Betta
Food: Crisps, algae wafers (veggie and protein) daily. Betta gets a small amount of "Betta Food Pellets". Weekly offerings are bloodworms and/or Tubifex worms. Plecos LOVE cucumbers and the silver dollars enjoy romaine lettuce leaves.
I do 50% water changes every week and clean my canister filter every 2 weeks (suggested is once a month but I do tend to overfeed with the silver dollars). Two of my peppered Corys are ill. Both have turned a dark, almost, black. Listless, no eating. The larger of the two (female) is at least 3" long and she's just over 6 years old. The smaller (male) is about a year old and he is the same. The female has ragged fins and the male has a "scrape" on one side of the his tail where the paler "flesh" is showing and for a day or two had a red ring around the lower half of his eye orbit.
That has disappeared. The only outward sign of illness I have noticed is the female had an episode of her chronic swim bladder disease. From time to time (every 6-8 months), she will float to the water's surface and end up laying on her side for part of the day. I always withhold food and within 8 hours, she's great again. This happened last week. I was unable
to do my regular weekly water change last Saturday, because I had the flu.
So, my parameters are as follows:
pH 7.5
Nitrate: 5
Nitrite: 0
Ammonia: 0
The female is my favorite fish. She's typically happy and LOVES water changes. She is just listless and I think she may have a little spot on her forehead, but I really can't tell with the dark color. I would sincerely appreciate any advice you can offer. All the other fish in the tank are happy and acting normally. I do notice some dark-looking (dark brown) algae or slime just beginning to form on my plastic plants, but this is something that I get regularly and clean each week.....
Thanks!
PS - Going to attempt to get a couple of pics to send as well
<<Would start by reviewing the environment, as Bob suggests. Corydoras paleatus is a low-end tropical species that can be stressed by overly warm conditions; 22 C/72 F is ideal, and if you're keeping other tropicals that like cooler water (such as Danios, Neons, Swordtails and Platies) then doing a good-sized water change with cooler water can pep the fish up. If cooling the tank isn't an option, add an airstone and/or another filter, because lack of oxygen rather than raw temperature is the thing that stresses them. Ditto more frequent water changes just to improve conditions generally. Now, reddish or whitish flecks on the fins and between the armour plates (scutes) is usually a sign of bacterial infection. Early on, the sorts of antibiotics used for Finrot can work nicely. There's something called Corydoras "Red Blotch" Disease that does plague these fish from time to time. It's probably triggered by an environmental shortcoming of some sort. I've written about the disease over at Fish Channel, here:
http://www.fishchannel.com/fish-health/disease-prevention/red-blotch-disease.aspx
Take a read. Hope this helps, Neale.>>
Re: Peppered Cory Illness      7/1/16

THANK YOU BOTH! I took some pics at lunch. They are attached. Perhaps temperature is an issue. I had been keeping the tank at 78-80 for angels that I previously kept (gave that up - no luck with that breed of fish), and I do recall my peppers doing much better with cool water at 72-74.
<Yes>

Oh, if it could be that simple.....please let me know what you think. I know my tetras and Plecos do great at lower temps....I believe the silver dollars will as well.
<They should; yes>
The pic of my female Cory on the red gravel substrate was within the first couple of months after I adopted her from my brother. I thought this would be helpful for comparison. THIS is what I'm used to seeing with her....and the changes may be subtle, but she's very special to me. The remainder of the pictures were taken today. The fish with the skinned up tail section (last two attachments) is the little male. The rest are of my female. The torn fins could be the result of the horrible advice I received 2 months ago from my LFS when they suggested tiger barbs would be good in this tank..... wow, were they wrong.
<Oh yes; too nippy>
I had those guys less than 5 days and they were ravenous, BUT I don't recall seeing any of this fin damage. When I compare the two pics of my female, her eyes may look a bit enlarged? She's always had such large ones....
<Both the before and current pix eyes are indeed too large>
I will definitely do a 50% water change tonight and slowly lower the temperature.
<Good>
I'm pretty careful with the lettuce and Cukes, but please let me know if there is a specific manner of cleaning these foods before adding to the tank.
<Soak them in tap water over night before offering. DO test the soak water for nitrates... telling>
I typically serve raw after about a 2 minute thorough rinse under lukewarm water.
<Again; the soak>
THANKS again, you folks are SO knowledgeable and it is extremely reassuring to have a source of experience to go to in these times of illness with our little finned friends.
<A pleasure to share; offer aid to other aquarists, humans who would better their understanding>
Kristi A. Jones
<BobF>


Re: Peppered Cory Illness /Neale       7/2/16
Thank you! Will follow all suggestions and let you know how they do....just two more questions:
1. Do you see evidence of an infection in the body condition of either fish?
<You can't really tell this by looking at a photo. I'd assume so, and medicate as per bacterial infection. It won't do any harm, and will help if bacteria are at play here.>
2. Do you feel the large eye issue is PopEye or is there something I need to do to that end?
<Pop-eye tends to fix itself when environmental issues improve, and assuming a secondary bacterial infection doesn't set in (again, another good reason to use anti-bacterial medications). Corydoras do get a bit "bug-eyed" when stressed, but usually recover from illness well, if the problem is caught early. Epsom Salt helps Pop-eye, so again, I'd do this alongside the antibiotics, as previously discussed.>
Much appreciated!
<Welcome. Neale.>

Bronze Cory Could Be Ill.       12/2/14
Hi,
I'm not sure how serious this is, but last night I saw one of my seven bronze catfishes lying on its side.
<Mmm; Callichthyids do this at times>
I examined the fish as closely as I could, and found nothing that appeared to be obvious. I've since seen it sitting straight up as normal, though it will sometimes lean a bit to one side.
<Also natural>
One fin (pectoral) looks that it might be smaller than the other, which, I imagine, won't help with stability?
<This lack of conformity does occur quite often as well>
I've heard that their fins are supposed to grow back rather quickly?
<Not always; no>
To sum up, it appears to be behaving somewhat normally. I don't know if this would factor in it, but I added the rest of the substrate to the tank at the weekend, and moved things around a bit / general tank maintenance - albeit quite thorough. Perhaps this has stressed the little creature out. Water parameters are good; I've recently moved over to R.O. since my tap water had too high nitrates.
<Not entirely to RO I hope/trust. These fish and almost all other aquatic life need mineral content... You do have alkalinity from adding, re-adding supplements?>

What do you suggest I might do? Turn up the temperature / Epsom salts?
Separate if it gets worse?
<Either a product to replace solids... Like: http://www.seachem.com/Products/product_pages/DiscusTrace.html
or some blended in tapwater for same>
Sorry I can't be more factual than this.
By the way, how long should raw / lightly cooked vegetables be left in the tank before being removed (24hrs?).
<About this long; yes>
Thank you, as always.
Kind Regards,
Stephen.
<I would not panic re this one Cory... am going to ask Neale to reply separately. Cheers, Bob Fenner>
Re: Bronze Cory Could Be Ill.   12/2/14
Hello Bob,
Thank you for your email.
Just to answer your question :
Your comment was : <Not entirely to RO I hope/trust. These fish and almost all other aquatic life need mineral content... You do have alkalinity from adding, re-adding
supplements?>
^^ Yes, I add minerals to the water with every water change (twice a week).
The GH is currently 6, and is very slowly being increased until it is around 10 (for the introduction of platies).
<Ah, very good>
Thanks for passing this on to Neale, too.
Many thanks.
Kind Regards, Stephen.
<As many welcomes. BobF>

Bronze Cory Could Be Ill.    /Neale    12/2/14

Hi,
I'm not sure how serious this is, but last night I saw one of my seven bronze catfishes lying on its side. I examined the fish as closely as I could, and found nothing that appeared to be obvious. I've since seen it sitting straight up as normal, though it will sometimes lean a bit to one side. One fin (pectoral) looks that it might be smaller than the other, which, I imagine, won't help with stability?
<Could easily be a deformity; if the fish is otherwise healthy and feeding, do not worry.>
I've heard that their fins are supposed to grow back rather quickly?
<Membranes yes; fin rays, yes; underlying bone, not so much.>
To sum up, it appears to be behaving somewhat normally. I don't know if this would factor in it, but I added the rest of the substrate to the tank at the weekend, and moved things around a bit / general tank maintenance - albeit quite thorough. Perhaps this has stressed the little creature out.
Water parameters are good; I've recently moved over to R.O. since my tap water had too high nitrates.
<What water chemistry are you maintaining? How are you intending to keep pH stable? RO or rainwater are fine, but need to be mixed with a source of minerals. Best is commercial Discus Buffer; easiest is some ratio of RO to tap water (say, 25% tap, the rest RO); cheapest is some version of the Rift Valley Salt Mix described elsewhere on WWM. Do understand that general hardness (dH, often augmented with Epsom Salt) has little/no impact on pH buffering; carbonate hardness (KH, augmented with baking soda) is the
chemical that maintains alkaline conditions and neutralises acids. With Rift Valley mineral salts you'll inevitably have a pH above 7, but that's fine, as Corydoras are happy between 6-8.>
What do you suggest I might do? Turn up the temperature / Epsom salts?
Separate if it gets worse?
Sorry I can't be more factual than this.
By the way, how long should raw / lightly cooked vegetables be left in the tank before being removed (24hrs?).
<As long as you want. Usually people remove them as they decay, but oddly enough, one expert catfish keeper I know points out this is exactly when fish are able to digest them, lacking the ability to digest terrestrial plant matter otherwise. Within reason, such plant matter is messy rather than harmful to water quality, so observe the behaviours of your fish and act accordingly.>
Thank you, as always.
Kind Regards,
Stephen.
<Cheers, Neale.>
Re: Bronze Cory Could Be Ill.   12/2/14

Dear Neale,
Thank you for another informative email. :)
Yes, I do add minerals to the R.O. water. The GH is currently 6, and is being slowly increased until it reaches around 10 (for platies).
<I did see this comment on your reply to Bob... want to stress, make clear that GH has little/no impact on pH stability, does not provide buffering capacity. In most situations KH is more important to freshwater aquarists than GH. Would encourage you to measure KH promptly, and ensure it is not zero if you are relying on hardness alone to buffer against pH drops. 4-5 degrees KH would be the minimum, I think, for casual fishkeeping with mixed species set-ups. If you use Discus Buffer, then KH can be ignored.>
Once again, many thanks for all your help. :)
Kind Regards, Stephen.
<Cheers, Neale.>
Re: Bronze Cory Could Be Ill.   12/2/14

Hello Neale,
I test the KH alongside the GH every week (usually twice a week). The KH is currently consistently between 8 and 10 (for several months now).
<Fine, even ideal for casual fishkeeping.>
I didn't know that it's as important as the GH.
<Not necessarily "more important" but "differently important". In short: general hardness affects osmoregulation, the ability of fish to keep the balance of salts and water inside their tissues just right. Soft water fish and hard water fish are "tuned" to maintain this balance in specific ways, and general hardness is a (the) factor determining how well they can manage. As we've already discussed, carbonate hardness is more about keeping a steady pH between water changes. Normal fish tanks experience a pH drop between water changes for various reasons, but carbonate salts in the water will inhibit this. So if you're keeping seriously soft water
fish, such as Cardinals, then a low GH is important. But if you're making up aquarium water from RO or rainwater, then KH will be important if you don't use Discus Buffer instead. Put another way, GH may determine what fish we choose; KH predicts how stable aquarium conditions will be.>
That is why you chaps on here are such a great source of information, - and why I trust this service over anyone else! :)
<Thanks for these kind words.>
Once my JBL aquadur minerals are used up, I will look at the discus one that you and Bob mentioned. I've started buying SeaChem products recently, as they get such a good rep. Gone is the API rubbish! :D
Kind Regards, Stephen.
<Cheers, Neale.>

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