multiple fish showing unhealthy behavior

[_cpate3_]

I understand everyone is keying in on aggression - but the rapid breathing symptom is worrisome. Fish will breath rapidly if being chased around, but that will settle down when they are not actively being chased. I’m also wondering why there would be widespread aggression in a tank that had been operating problem free for a time.

Here is a possible scenario - the fish ave some disease issue causing the rapid breathing. That weakness makes them more prone to being harassed by other fish

The rapid breathing was a today thing only, he had completely normal behavior the past few days. And no other fish in the tank are breathing that heavily. When I took the body out of the tank, I saw a huge bruise on its stomach which I didn’t catch i thought it was just the fin so he was worse off than I thought

 

[_cpate3_]

The rapid breathing was a today thing only, he had completely normal behavior the past few days. And no other fish in the tank are breathing that heavily. When I took the body out of the tank, I saw a huge bruise on its stomach which I didn’t catch i thought it was just the fin so he was worse off than I thought

Unfortunately with fish aggression and damage - the solution is to immediately isolate the affected fish (or the one doing the damage) - whether with an acclimation box or a new tank, etc etc. In any case - with regards to your fish - it seems like a parasite is very unlikely. I would treat the damaged fish in a hospital tank with a broad spectrum antibiotic. (kanamycin/neomycin)

The only other thing I’ve noticed is an outbreak of pineapple sponges in the tank if that means anything?

 

[MnFish1]

The only other thing I’ve noticed is an outbreak of pineapple sponges in the tank if that means anything?

I can think of vague reasons how/why this could be related - but - they are not needing to be mentioned since there would be other issues in the tank so - short answer 'no'