Cardinalfishes are a family, Apogonidae, of ray-finned fishes found in the Atlantic, Indian, and Pacific Oceans; they are chiefly marine, but some species are found in brackish water and a few (notably Glossamia) are found in fresh water. A handful of species are kept in the aquarium and are popular as small, peaceful, and colourful fish. The family includes about 370 species. They are nocturnal, spending the day in dark crevices within the reef. At least some species brood their eggs inside the mouths of the males.