This was previously know as Mesogonistus chaetodon. It's really a
coldwater fish, having a natural range from Maryland to New Jersey, but
has apparently often been sold as a tropical in Europe.
Hans Frey speaks highly of it, describing it as
a rather shy but attractive fish that moves gracefully in shoals. He recommends
a minimum temperature of 8° C and says they are not difficult to breed, the
male guarding the eggs cichlid fashion. A few years ago the black banded sunfish
was was known as the "poor man's angel" being quite highly prized in the
hobby. It is little seen in dealer's shops these days, perhaps being
overshadowed by the real angel which can now be bought at bargain prices.