I found a 55 gallon tank on craigslist, got it all hooked up yesterday and the one agressive angelfish is STILL attacking the other. I found the wounded one upside down and pressed against the filter so I unhooked him and he seems to be swimming fine. Is the aggressive fish just preying on a weakened fish or do I just have an aggressive fish that needs to be relocated? Any tips on other fish to put in the tank? I have two african dwarf frogs, about 10 tetras, two tiger striped cat fish of some kind, one pocastomas.