Pajama Cardinalfish

Sphaeramia nematoptera

Also known as Pyjama Cardinalfish, Spotted Cardinalfish, Coral Cardinalfish

SaltwaterFish

Pajama Cardinalfish (Sphaeramia nematoptera) — Brian Gratwicke · CC BY 2.0

Care at a glance

Temperature: 72–81°F (22–27°C)
pH: 8.1–8.4
Adult size: 3.1 in (8 cm)
Minimum tank: 29 gal (110 L)
Temperament: Peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Easy
Breeding: Medium
Rarity: Very common
Reef safe: Reef safe
Origin: Indo-West Pacific (Java to Fiji, north to Ryukyu Islands)
Family: Apogonidae

Overview

Pajama cardinalfish are reef safe and leave corals and clams alone, but they are not fully invertebrate safe since they will eat very small ornamental shrimp that fit in their mouths. They are among the more peaceful marine fish and do well as a pair or a small group, though individuals can bicker or pair off and get pushy toward each other when breeding, so give a group room to spread out. Offer frequent small meaty feedings of mysis and enriched brine.

In the wild

Pajama cardinalfish live over sheltered lagoon reefs and among branching corals across the Indo-Pacific, where they hover in loose groups by day and become more active at dusk. In the aquarium they like a tank of at least 110 liters with rockwork or coral branches to hang beneath and open water in front of it. They are largely nocturnal feeders in the wild, so they appreciate cover during bright daylight and settle quickly into a calm community.

Good to know

The striking pattern (a green face, a bright orange band, and red polka dots on a pale rear body) breaks up the fish's outline against a busy reef backdrop. Like other cardinalfish it is a paternal mouthbrooder, the male incubating the fertilized eggs in his mouth for roughly one to four weeks before releasing well developed fry. Those fry still need tiny live foods such as rotifers and copepods, which is what makes rearing them harder than spawning them.

Did you know

A group of pajama cardinals will often stack up almost motionless under the same coral branch during the day, drifting together like they are all wearing matching pajamas, then spread out to hunt once the lights dim.