Disease killing our Corydoras

[Katiestl]

I've tried posting in forums before and people just tell me it's ich, but I haven't ever had a fish with ich in the last 20 years and know what it looks like.  Sorry for length--it's confusing.

Parameters--55 gallon tank. All normal. Ph is 7.5. No ammonia, no nitrites, occasionally get minuscule nitrates as our tap has nitrates in it, but nothing measurable in tank. We use mostly RO, but add tap to warm and add some minerals. It does not affect the fish. I had the tank go really wrong once and no disease occurred before I fixed it-- this was years ago. We have two canister filters in this 55 gallon, one for 55 gallon tank and one for 110. It is clean but grows algae to the extent that my plants die. natural gravel bottom.

My corys have a mystery disease. Color darkening, no eating, lethargy and rapid breathing to seizures, breathing stopping.

The only disease I have ever cured in fish is columnaris(what the ich actually was after consulting local guy).

I lost my last snail 3 weeks ago. It was over a year old, the fish ate it before I found it as always, no more snails. I have one goldfish(6yo) and had 4 corys. 1 is 3.5 yrs old and survived the columnaris from 2 years ago plus one weird parasite that had no cure but looked like tiny pieces of rice on their skin that would multiply as the disease progressed. All antiparasitics failed. Changing the water every 48 hours for 10 days cured them. With every water change, more would fall off--no idea why. Not ich. Slow spreading as in weeks, not days.

 

Anyway, that was all over 1 yr ago. These 3 newer corys I've had for just over 1 yr. (I had some ottocats a few years ago who died in the exact manner). New tank as of Aug 2021. The smallest two had not grown much in the last year, the bigger one tripled in size to match my original cory(they said he was panda but looks nothing like online photos, others are green). Two weeks ago, smallest cory was lethargic, within two days, he was dying. No external changes except a color change--he darkened. All sparkle was gone in a few days. No rot, not redness, no marks of any kind, just dark. No, it isn't burn from ammonia, there isn't any in my really clean tank. So, I euthanized it when he started swimming erratically. Not swim bladder--like psychotic, looked like a seizure. he would dart. run into objects, swim in circles straight up and die--literally stop breathing. Float to bottom upside down and wake up 10 seconds later. Repeat this times 1000. Other fish started to attack. He couldn't catch his breath. Due to lack of growth I decided he had an internal parasite. he looked thin. I carefully watched the other two. 3 days ago the biggest newer cory was sitting very still. He actually left a gap in the algae because he has been sitting there so much. He has darkened a lot. He is breathing fast. Other two now sitting still as well. I ran searches, gill flukes cause all symptoms, curable with API general cure. 1st dose caused no change, disease progressing, no eating at all. They say just to put it in water but the flagyl and praziquantel should need to be ingested for anything intestinal. Second dose tonight. There are no outward symptoms other than darkening, no sparkles. His fins are slightly clamped when sitting but otherwise perfect. I don't really have a good photo to compare a before and after of color. I checked the body of the dead fish very closely--no marks, no visible disease. I assumed internal parasite until realizing that gill flukes cannot be seen.

 

Please, any ideas? I watched an entire aquarium die like this 5 years ago. Each minnow or Ottocat would stop eating, go insane and die or be euthanized if I found them struggling. Nothing cured. I tried all the usual meds. I've never had an antiparasitic work in fish, even on things I could see. I'll be really upset if our goldfish dies, plus he loves his cory friend, they school together.

[TheSwissAquarist]

On 11/5/2022 at 8:39 AM, Katiestl said:

I've tried posting in forums before and people just tell me it's ich, but I haven't ever had a fish with ich in the last 20 years and know what it looks like.  Sorry for length--it's confusing.

Parameters--55 gallon tank. All normal. Ph is 7.5. No ammonia, no nitrites, occasionally get minuscule nitrates as our tap has nitrates in it, but nothing measurable in tank. We use mostly RO, but add tap to warm and add some minerals. It does not affect the fish. I had the tank go really wrong once and no disease occurred before I fixed it-- this was years ago. We have two canister filters in this 55 gallon, one for 55 gallon tank and one for 110. It is clean but grows algae to the extent that my plants die. natural gravel bottom.

My corys have a mystery disease. Color darkening, no eating, lethargy and rapid breathing to seizures, breathing stopping.

The only disease I have ever cured in fish is columnaris(what the ich actually was after consulting local guy).

I lost my last snail 3 weeks ago. It was over a year old, the fish ate it before I found it as always, no more snails. I have one goldfish(6yo) and had 4 corys. 1 is 3.5 yrs old and survived the columnaris from 2 years ago plus one weird parasite that had no cure but looked like tiny pieces of rice on their skin that would multiply as the disease progressed. All antiparasitics failed. Changing the water every 48 hours for 10 days cured them. With every water change, more would fall off--no idea why. Not ich. Slow spreading as in weeks, not days.

 

Anyway, that was all over 1 yr ago. These 3 newer corys I've had for just over 1 yr. (I had some ottocats a few years ago who died in the exact manner). New tank as of Aug 2021. The smallest two had not grown much in the last year, the bigger one tripled in size to match my original cory(they said he was panda but looks nothing like online photos, others are green). Two weeks ago, smallest cory was lethargic, within two days, he was dying. No external changes except a color change--he darkened. All sparkle was gone in a few days. No rot, not redness, no marks of any kind, just dark. No, it isn't burn from ammonia, there isn't any in my really clean tank. So, I euthanized it when he started swimming erratically. Not swim bladder--like psychotic, looked like a seizure. he would dart. run into objects, swim in circles straight up and die--literally stop breathing. Float to bottom upside down and wake up 10 seconds later. Repeat this times 1000. Other fish started to attack. He couldn't catch his breath. Due to lack of growth I decided he had an internal parasite. he looked thin. I carefully watched the other two. 3 days ago the biggest newer cory was sitting very still. He actually left a gap in the algae because he has been sitting there so much. He has darkened a lot. He is breathing fast. Other two now sitting still as well. I ran searches, gill flukes cause all symptoms, curable with API general cure. 1st dose caused no change, disease progressing, no eating at all. They say just to put it in water but the flagyl and praziquantel should need to be ingested for anything intestinal. Second dose tonight. There are no outward symptoms other than darkening, no sparkles. His fins are slightly clamped when sitting but otherwise perfect. I don't really have a good photo to compare a before and after of color. I checked the body of the dead fish very closely--no marks, no visible disease. I assumed internal parasite until realizing that gill flukes cannot be seen.

 

Please, any ideas? I watched an entire aquarium die like this 5 years ago. Each minnow or Ottocat would stop eating, go insane and die or be euthanized if I found them struggling. Nothing cured. I tried all the usual meds. I've never had an antiparasitic work in fish, even on things I could see. I'll be really upset if our goldfish dies, plus he loves his cory friend, they school together.

Have you tried a course of Expel-P and/or Kanaplex?

@Colu seems to give good advice on diseases.

Could you please post some pictures?

[Katiestl]

Kanaplex is for dropsy or septicemia, they don't have this--those both have obvious signs that I have seen before. Not a fan of that med at all. Seachem makes wrong claims about it right on their site. If it's an antibiotic then it cannot cure a fungus as they claim--simply isn't possible. They claim it's safe for snails, then tell you to remove all snails before using. I've had problems with seachem products in the past and am actually responsible for them changing their label for two products after they lied about them. I won't throw useless antibiotics into the tank to destroy what defenses they have. That is not a first line antibiotic, there are safer ones I'd use first. I have killed fish by giving wrong treatments in the past. there are no photos. They look 100% normal. No fin rot, no dropsy, no eye bulging. I cannot photograph rapid breathing and without a comparison photo, he is just darker than he was.. He isn't blackened, just the green is now gray, the orange is now reddish, not bloody. If you didn't know what he looked like 3 days ago, you'd think he was a normal fish other than behavior. I magnified the dead fish, nothing visible on him. This fits all the symptoms of gill flukes but meds not working. Especially if the snail had the flukes first and they ate him and caught it. I figured the snail died of old age, mystery snails aren't supposed to live long.

[TheSwissAquarist]

On 11/5/2022 at 9:54 AM, Katiestl said:

Kanaplex is for dropsy or septicemia, they don't have this--those both have obvious signs that I have seen before. Not a fan of that med at all. Seachem makes wrong claims about it right on their site. If it's an antibiotic then it cannot cure a fungus as they claim--simply isn't possible. They claim it's safe for snails, then tell you to remove all snails before using. I've had problems with seachem products in the past and am actually responsible for them changing their label for two products after they lied about them. I won't throw useless antibiotics into the tank to destroy what defenses they have. That is not a first line antibiotic, there are safer ones I'd use first. I have killed fish by giving wrong treatments in the past. there are no photos. They look 100% normal. No fin rot, no dropsy, no eye bulging. I cannot photograph rapid breathing and without a comparison photo, he is just darker than he was.. He isn't blackened, just the green is now gray, the orange is now reddish, not bloody. If you didn't know what he looked like 3 days ago, you'd think he was a normal fish other than behavior. I magnified the dead fish, nothing visible on him. This fits all the symptoms of gill flukes but meds not working. Especially if the snail had the flukes first and they ate him and caught it. I figured the snail died of old age, mystery snails aren't supposed to live long.

Parasites....🤔?

Impossibles for them to all catch cancer at the same time......are they picked on at all??

[Colu]

I think you could be dealing with a parasitic infection what I would do is feed Expel p in food for 7 days feeding a small amount twice a day then follow up with a course of general cure or paracleanse then repeat the Expel p in two weeks then follow up with another course of paracleanse or general cure that will treat most types of commonly encountered parasites