Once I realized this guy was sick, and treated him, I decided to feed clams. They are easy to get at Costco. I just freeze them and soak them in vitamins before I feed him. He is eating lots but hasn't grown much. I still feed pellets but he has no interest in them. I don't think these guys are designed to eat pellets. These teeth need clams. He is well acclimated now and eating like a pig. 4-5 clams, and a few shrimp every 2 days . My arowana is no longer eating pellets now but there are worse things I guess. They are all getting along now and the arowana is growing back his fins. I haven't had any more incidents of late. Everyone knows where they stand in the pecking order.