I have a rather large black brittle star. I would guess tip to tip about 18 to 24 inches with a center larger than a silver dollar round. I am pretty sure it eats fish as I got a cleaner shrimp yesterday and I cannot find it or any molted skin anywhere. It has eaten little fish in the past. Time to get rid of it. I will be moving it to my sump temporarily where it can eat whatever goes through the overlfow, but I think it would be better for a large tank with large fish. I am in Louisville KY for anyone that wants it. 502-572-7280.