I maintain a large FW community tank that includes a large (8") Festivum cichlid, Mesonauta insignis, as well as an 7" Marginated Madtom, Noturus insignis, raised from a hatchling netted in a nearby creek. (Yeah, I know they're odd tankmates.)
Lately, I've been finding my Festivum sporting parallel 3/4" crescent shaped wounds on either side of the hump of his back, just forward of his dorsal fin, as if someone had chomped him. The only 'someone' in the tank large enough to make such a bite wound is the Madtom, whose mouth is about 1" across. The wounds heal up with treatment, but I hate for the Festivum to continue to be injured. I've never actually seen the Madtom bite him, although they occasionally spar. The only other way I can imagine the Festivum getting injured is when he occasionally breaches and bangs against the inside of the aquarium lid. This wouldn't explain the symmetry of the injuries, however. Any of you with experience with Madtoms - is it likely he might be attacking the Festivum, a much larger/bulkier fish?
I'm seriously considering re-homing this fish, but I fear returning him to a cold creek after life in a warm aquarium would have unhappy consequences. I don't have a spare tank or even room for another tank and would love to place him with someone else interested in native catfish. He's quite healthy and a really interesting fish, but I'm not willing to continue placing my Festivum at risk.
If you're interested, I'm in North Carolina near Winston Salem. Helpful suggestions are welcome.