one of my ornatipinnis is nipping at another slightly smaller one, they have only resontaly started doing it, it has only started picking on the one i have 2 othere which it is fine with, any reason why just that one?
Move stuff around a little in your tank and at worst move everything out for a little while. Arrange things around to so that bichirs won't get to attached to certain areas of your tank. If you don't have any hiding places in your tank then I sugggest putting some in the tank so that each bichir can go to his or her own little area to chill out. Aggression is going to happen in a bichir tank, and as long as there are no injuries it isn't a huge issue. My bichirs nip at each other all the time. I move stuff around and they're ok, then they grow comfortable with their new spots and start nipping again. I move stuff around and the cycle continues...