Fin damage - disease or predation?

My 40-gallon has hosted a baby gray snapper for the past few weeks. I would never have managed to ID him without this forum, but once someone told me what he was, I checked images on the web, and he is a perfect match. The kids have named him "Snappy."

Here's the thing--I have never witnessed Snappy eating a thing, but he shows no signs of malnutrition. Also, there has been a marked decline in the small topminnow population. I assume he's eating them after dark. Not a problem for me so long as he leaves my gobies alone.

HOWEVER, I've noticed one of my rainwater killifish and one of my mummichugs have damage to their tailfins. I'm wondering whether this is the result of disease or of Snappy's attentions. Is there any way to tell? Are there other signs that would be present if disease is the problem?

Any advice appreciated.

just keep an eye on it.

my fishes fins get damaged every once in a while, and they just heal right up.

i've never actually seen any fins get damaged, but i know that my crayfish has damaged a few fins, and i assume aggression between fish has also caused some other damaged fins. i think some fins have been damaged by decorations too.

if there is aggression in your tank, the damaged fins could be a direct result of the aggression, or it could have happened while the fish was fleeing.

since i haven't had any diseased fins, i couldn't really tell you what to look for. but my eyebrows would be raised at any redness or whiteness or fungus or anything else out of the norm.

if your damaged fins aren't infected then they'll just heal up in as little as a few days or up to a month(depending on how badly damaged) without any special attention.

all of the above is my experience with damaged fins, others may tell you otherwise.

Thanks Dave!