I have two AFC's and one of my girls is very large and eats everything that enters her path. with that being said I have been through a lot of different fish and the only fish I have been successful with are gourami's and that is only because they are to big for her to fit in her mouth. My other frog is not as aggressive but they both will still try to grab the gourami's if they swim in front of them. I think the gourami's "feelers" help them stay out of danger as well because they are able to swim away before the frog can get to their fins.