So I recently bought a Tiger Shovel Nose Catfish from my LFS (he's around 6 inches) and I put him in my 500 with some silver aros and 2 bichirs (both 4 inches), it was all good for the first week then I started to notice that my TSN's fins and barbels started to rip and tear so I put in some Melafix cause I thought it was finrot. The night after I walk in to the basement (where my tank is) looking for my phone and I see one bichir biting feraciously on my TSN's dorsal fin and the other on it's tail. I seperated them but I don't understand why this happens when the bichirs are smaller than it and is it ok to reintroduce him maybe when he is a little bigger cause I the TSN won't last very long in my 40 Quarintine tank.THX