I highly recommend getting a bucket or some plastic bin and set it up as a quarantine tank, it will help them recover better and not unnecessarily stress the rest of your fish

Thanks for the heads-up.

In my experience it looks like a bacterial infection arising from the stressed cories, the temperature increase may have triggered this. Is it a white film growing on the fish? I recommend quarantine and paraguard treatment. You can do a salt dip, that may help a great deal but it can also shock the...

Update, the peppered ones died after not eating for a few days.
I have quarantined the rest again, they seem to be fine and the lumps are reducing.
I am considering doing a 80% water change, removing all gravel and boiling the ornaments and wood.
Any thoughts?

Im having this same issue, the fish behave and eat fine.
When i quarantine and treat it with paraguard it disappears. When I put them back into the main tank it come overnight.
Seen this happen only to bronze/emerald corys.

Hi everyone, I am new to this forum but not new to cory catfish. Ive been raising and breeding catfish for over 3 years but some kind of new disease ive never come across has stumped me. Tank details: 20 gallon with plants drift wood and decorations ; Substrate: white sand Filtration: external canis...