I have 2 small 4" Payara (scombs) in my 55gal. The slightly smaller one has had some significant damage to its tail a few times in the past weeks. I treated it with melafix and it was healing up nicely from the first incident, but then this morning he was shredded worse. Melafix-ed the tank, but I don't know if the other Payara is doing it or if one of my well-fed polypterus are trying to eat it? What would you all guess?
STNDFSH?

STNDFSH?

