Sick Catfish

[headbanger_jib]

did you change the tank or any filter recently
the last time this happened to me after a move to the 180g rubber maid and when they started dying i moved the remaining to a different set up(1 TSN and 1 ARTC)
there were no fin damage so the ARTC wasn't doing any damage(just so that no one starts grilling me)
everything was alright the params , the temp , PH
lost my hybrid, and TSN to this

 

[Onion01]

well, I was 100% certain one of mine was gonna be dead by this morning. He's not. He's even starting to color up. I'm holding my breath, but i'm also gonna do a bunch of water changes. I'll keep you updated

 

[TLkmDN]

honestly, just get a freaking huge tank...like no smaller than 6 feet...cause water params barely fluxuate in bigger tanks plus it gives room for error.

 

[Onion01]

I do 10% wc every day, check the temp, pH, ammonia every 3 days on my gulper tanks, and everything is always fine

 

[octofasciatus]

What's the aeration like.? I had similar symptoms a few year in one of my smaller tanks where my fish kept dropping due to lack of dissolved oxygen.