If it doesnt eat the dwafs it will soon be the vice versa case. Most puffers are true monster fish. I would say, if you want monster fish and you only have a small tank, get just dwarfs. Angel fish are not monsters by any means what so ever and although the butterfly fish are cool I would not consider them monsters either. Frogs cannot be monster fish because....well....they are not fish. Puffers are seen as cute little balloon shaped fish, but in reality they are highly developed predators with two razor blades hidden behind their little smile.