help-fish are dying fast

help

I have many aquariums. current problem is only in one. 80 gallon. 7.1 ph, ammonia test ok, nitrate ok.

I have had 5 fish in this tank for a year or 2 now. They were 2 pan fish (warmouth & brim), one bass, Catfish (channel) and a plecko.

On Sunday I noticed a small patch of skin had turned white on the bass's back, but otherwise fine. I treated for fungus. Within hours he was dead. So, I treated with an antibacterial medication as I have never seen a fungus kill this fast. a day later both of the pan fish developed a white patch on the side which within hours was on the tail too then about 24 hours later both pan fish died.

This morning the catfish developed a white spot about half an inch in diameter . When I came home from work and the catfish is in severe distress. About half of his body is white. The original spot is now starting to sink in and another spot is turning red. Fins are uneffected and mouth is just starting to turn white. Gills, mouths and fins were all uneffected on the other 3 fish as well. The other 3 didn't turn red and the white areas didn't sink in, they all died well before this stage

The white spots are large, abnormal shaped, not fuzzy, were not infected looking and were not looking at all like a lesion until this one spot on the catfish. And what ever it is, it kills quickly.

Any ideas? I have never seen anything like it and the closest think I have seen since looking today is one picture from a hatchery with a aeromonas infection, however all the other photos of aeromonas infections look nothing like it.

please any suggestions welcome. I hope to save the catfish. The plecko is showing no change yet.

the photo below has been color adjusted so you can see the spots. The top one is the only one sunken in now and the othe side of the fish from the tail to his stomach is now mostly white. I can email more photos if you think it would help

Thanks

I forgot to mention. I do 25% water changes weekly and have done 1 50% on Monday. It is getting worse already. here is another picture and yess all that white is actually white. You are seening the belly and the side and another spot is turning red.

Thanks

Hi.

Sorry about your fish.

The spots sound too big to be ich. The fact that you said that they aren't fuzzy looking leads me to believe that it isn't fungus.
The "white patches" lead me to believe that it is columnaris disease. You have to treat your fish early with anti-bacterial medications before it gets really bad. After that antibiotics "may" work.

Ok. I've had this once before.
1. If you have another (smalller) tank, net out all the fish and put them in there. Do a 100% water change on the original tank, while putting a full dose (or more) of Malachite green and/or maracyn in the tank holding the fish.
2. If it's what I had, the 'slime' should start sloughing off, leaving a huge mess in the tank, but a healthy fish!!
This disease killed a bunch of my fish, and luckily I rescued most of them and they are alive and swimming now. This stuff kills in hours, and I almost lost my 6" dojo loach to it.
Good luck!!!
Robin