Mesonauta festivus is an interesting cichlid related to angelfish and discus. Most commonly, fish traded as 'Flag Cichlids" are actually M. insignis, but these appear to be the real deal. Sometimes known as the Festivum, these fish get around the same size as angels, around 4" long. They are a peaceful cichlid and mix well into community aquaria with similar sized fishes. As omnivores, using a food with a bit of plant matter in it is a good idea.
These are juveniles around 1" long.