Pajama Cardinalfish

Sphaeramia nematoptera

Pajama Cardinalfish

Sphaeramia nematoptera

Other Common Names
Coral cardinalfish

Connected Coasts

Other Common Names

Coral cardinalfish

At the Aquarium

Connected Coasts

Appearance

Like other cardinalfish, this species has two dorsal fins. The pajama cardinalfish has a yellow head and a vertical black stripe below its first dorsal fin. This species also has large brown spots on the posterior half of its body.

The pajama cardinalfish reaches a maximum length of 8.5cm.

Habitat

Sheltered, coastal reef slopes and in lagoons with rich coral growth. Lives at depths as deep as 14m.

Diet

Small shrimps, crabs, and other small crustaceans.

Life History

The pajama cardinalfish lives amongst branching corals, especially Porites cylindrica, as well as Acropora and Anacropora corals. This species is considered social and often forms groups with 2 to 25 individuals.

After a courtship ritual is performed, the female releases a large mass of eggs which is then fertilized by the male. Like other species of cardinalfish, the male of this species engulfs the eggs with his mouth and stores them there for several days.

Once hatched, the pajama cardinalfish enters a larval stage where they drift and float in ocean currents. They eventually settle in coral reef habitats and find the branching coral they return to every day.

IUCN Status

Least Concern

Ecosystem & Cultural Importance

The pajama cardinalfish plays a vital role in coral reef ecosystems as they are a food source for a variety of predators and they help control several crustacean populations.

Distributed in the West Pacific from Sumatra, Indonesia east to Pohnpei, Caroline Islands, Fiji and Tonga, north to the Yaeyama Islands of Japan, the Philippines, south to northern Queensland in Australia and New Caledonia.

This animal is not native to the Oregon Coast, however is found in the larger Pacific Ocean. It lives in the Aquarium as part of our Connected Coasts gallery.

The pajama cardinalfish tends to remain hidden during the day and leaves the protection of corals at night to feed.

When males of this species incubate the eggs in their mouths they are unable to feed.

Citations & Other Resources

Allen, G.R., R.F. Myers, M. Santos, M.T.M. Mutia, B. Muyot, H. Arceo, H. and C.L. Nañola. 2022. Sphaeramia nematoptera. The IUCN Red List of Threatened Species 2022.
Myers, R. F. 1991. Micronesian reef fishes : a practical guide to the identification of the coral reef fishes of the tropical central and western Pacific (2nd ed.). Coral Graphics.
Randall, J. E., G.R. Allen, and R.C. Steene. 1990. Fishes of the Great Barrier Reef and Coral Sea. University of Hawaii Press.
Pushchin, I., and N. Aleskerov. 2024. Retinal ganglion cell topography and spatial resolving power in the pajama cardinalfish Sphaeramia nematoptera (Bleeker, 1856). Journal of Fish Biology, 104(5), 1299–1307. https://doi.org/10.1111/jfb.15680
Rueger, T., C. MacDonald, H.B. Harrison, N.M. Gardiner, G.P. Jones, and S.C. Mills. 2024. Strength of Sexual Selection and Sex Roles Vary between Social Groups in a Coral Reef Cardinalfish. The American Naturalist, 204(3), 289–303. https://doi.org/10.1086/731422

Pajama Cardinalfish

Pajama Cardinalfish

Other Common Names

At the Aquarium

Appearance

Habitat

Diet

Life History

IUCN Status

Ecosystem & Cultural Importance

Citations & Other Resources

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