I ahve had my ten gal for about a year now and recently i have noticed my two cories have peices like bite marks on there pectoral and top (dont know that one ) fin and there is a little les tail each day. ive checked for tail rot and i dont know what could be happening to them, they leave each other alone from what ive seen and the other fish leave them alone,not sure about my black khuli loach though. thanks for helping