Ruby Red Cardinalfish - Apogon coccineus

The little Ruby Red Cardinalfish (Apogon coccineus) has a ruby red semi-transparent body, as the name implies.

Cardinalfish are often overlooked in the aquarium trade but many make hardy, peaceful and even schooling additions to reef and fish-only aquariums. Species available in the aquarium trade are most often from the Apogon, Pterapogon and Sphaeramia genuses. Some are nocturnal and will hide for most of the day but others will remain out in the open during the day once acclimated to the aquarium. Many cardinals are schooling and can be kept in groups, especially as juveniles, but some larger or more aggressive cardinals should be kept alone or in large schools.

Larger cardinals may prey on smaller ornamental crustaceans and, in some species, small fish but most are community fish and can be kept with other peaceful to moderately active tankmates. They will not bother corals or most inverts; some often swim and hover in and around the branches of corals and spines of larger urchins.

Most cardinals are not picky eaters. With time, they may accept flakes and pellets but they can be giving a varied diet of meaty foods like brine shrimp, mysis shrimp, planktons and other similar items. Most cardinals are mouth brooders; the will hold their eggs in their mouth and fast until the young hatch and can feed on their own.