Pajama Cardinalfish

Sphaeramia nematoptera is a species of fish belonging to the Apogonidae family. It is a popular aquarium fish.

Description

It grows to a total length of about 8.5 centimetres (3.3 in) and features distinctive red eyes and a broad dark vertical 'waistband' with scattered red spots toward the tail. The Pajama Cardinalfish is a rainbow of playful colors. It has a greenish-yellow face, bright orange eyes, and a silver-based body dressed with a bold black scalar margin and a posterior dotted with orange polka-dots. It is considered to be of low vulnerability. The male pajama cardinalfish incubates the eggs in its mouth until they hatch.

Distribution

Throughout much of the western Pacific Ocean, from Java to Fiji, and from the Ryukyu Islands south to the Great Barrier Reef.

Habitat

Forms aggregations among the branches of Porites nigrescens and P. cylindrica in sheltered bays and lagoons. Disperses at night to feed close to the bottom.

In aquarium

Though its bold coloration may stand out, Sphaeramia nematoptera has a peaceful nature that lets it blend perfectly into any community saltwater aquarium. For the best care, the Pajama Cardinalfish should be kept in small schools in suitably sized aquariums of at least 30 gallons. Because the Pajama Cardinalfish is a slow and methodical swimmer, it should be housed with peaceful tankmates and offered a plethora of hiding places amongst rockwork or plants. Most Pajama Cardinalfish will tend to hide in sea grass or other plants. Some may also camouflage themselves against long spined sea urchins.

Like many other schooling fish, the Pajama Cardinalfish will form a strict hierarchy when kept in small groups within the aquarium. However, unlike some social fish, this member of the Apogonidae family does not use aggression to exert dominance over other cardinalfish.