Pajama Cardinalfish

Pajama Cardinalfish, Polka-dot Cardinalfish, Spotted Cardinalfish

Scientific Name:
Sphaeramia nematoptera

Maximum Size:
3.5” (9 cm)


The Pajama Cardinalfish is a member of the Cardinal fish family Apogonidae. They are sometimes called polka-dot cardinalfish due to a pattern of round spots on the posterior part of their body. The “polka-dots” are black on early juvenile fish, but turns red as the fish grow. They have a yellow-greenish face and a mid-body black band that runs from the first dorsal fin to the pectoral fin. The black band is a camouflage feature that helps them blend in between spines sea urchins and coral structures. Another interesting fact about the Pajama Cardinals is that they are mouth brooders. After the eggs are fertilized the male picks them up and guard the eggs in his mouth until they hatch. After the eggs hatch the male “spits out” the juvenile fish and they are on their own.


Pajama Cardinalfish originates from the Coral Sea in the Indo-Pacific area and can be found in areas around Northern Australia, Papua New Guinea, the Philippines and Indonesia.

Temperament & Captive Care

The Pyjama Cardinalfish is peaceful and an excellent choice for new marine aquarium hobbyists. They like to hang out in small schools of 5 or more individuals and are often found hovering in one place near caves or coral structures. They are nocturnal, which is evident from their big eyes. At night they split off from their groups and hunt for food by themselves. They are best kept in Aquariums of 30 gallons or more. Due to their peaceful nature they should not be kept with aggressive fish.


Pajama Cardinalfish will consume a variety of different food types. In nature their diet consists of small crustaceans, which they hunt at night. In the aquarium they prefer a meaty diet of frozen food such as mysis shrimp and brine shrimp. However, they will also eat pellets and flake food. Since they are nocturnal hunters it is preferred to feed them at night or during the twilight period.