Fish that are peaceful and docile make the best tank mates for angelfish. Species of fish that would thrive alongside angelfish include livebearers, tetras, rams, Krib’s cichlids, keyholes and many species of bottom feeders, such as corydoras catfish. That said, angelfish seem to do the best when they are kept in groups of five of more of their own species.
There are also many different amphibians and crustaceans that can coexist alongside angelfish in an aquarium. African dwarf frogs, apple snails, ghost shrimp and red cherry shrimp are just some examples of animals that get along with angelfish. It is important to make sure that whatever animal is chosen to be included in the tank alongside the angelfish is not smaller than 2 inches, as angelfish have been known to eat smaller fish and other animals. It is also best to avoid species that may nip at the fins of angelfish like oscars or the tiger barb. Fish that dart to and fro and display nervousness, such as danios, should also be avoided, as they may stress out the angelfish in the tank.
In addition to considering the species that inhabit the aquarium, it is also important to make sure that the aquarium is of sufficient size, as a tank that is too small will cause the angelfish to feel overcrowded and may lead to aggressive behavior between the angelfish and other fish in the tank.