Yellow Cardinalfish

About

Found across the Western Central Pacific from the Philippines to the Marshall Islands, this small cardinalfish, Ostorhinchus luteus, is one of those species that makes the most of its modest size. Out on the reef, it gravitates toward sheltered, clear-water spots in lagoons and along seaward reef faces, where groups gather under rocky ledges, tuck into crevices, or nestle improbably among the spines of sea urchins for protection. That same instinct shows up in the aquarium, where it appreciates caves, overhangs, and any nook it can call its own. Reaching only an inch or two as an adult, it is well suited to smaller reef setups and poses no threat to peaceful tankmates. Its diet in the wild consists of planktonic crustaceans and small invertebrates, and it actively forages both day and night, which makes feeding in captivity fairly straightforward. Most meaty foods of appropriate size are accepted without much fuss. For newer saltwater keepers looking to add some mid-water or lower-reef presence without the complications of a more demanding species, this little cardinalfish is a genuinely forgiving choice. Keep it with similarly mild-mannered fish and it should settle in without issue.