[billsreef]

The trials and tribulations of aquaculture.

It you think it's fin rot vs agression it would probably pay to treat him with some antibiotics, Nitrofuran or Maracyn II would be my top choices.

The biggest problem with mouth brooders is that they don't eat while brooding. This takes a toll on their reserves and immune systems. Considering how fast they spawned again after the first time, this is likely whats causing the current problem. So long as he's eating well he should fully recover.