Banggai Cardinalfish are an endemic species that is only found in the Banggai archipelago located in the south Pacific. Before I continue I just want to say that "Banggai" is the proper spelling, not Banngai, Bangaii or any of the other spellings that you might encounter.
This fish is usually a very calm fish that takes little interest in other fish except when tending to their eggs. It is best to keep them in pairs unless they are in a large tank.
The males are mouthbrooders, the female will defend the male while he is "holding" the eggs. Males will incubate the eggs for about 21 days and release fully formed young that will feed on newly hatched Artemia.
The most difficult part is getting the male to incubate the eggs until they are ready to be released. Artificially incubating the eggs is an option if the male doesn't hold them for the full term.