Pajama Cardinalfish (Sphaeramia nematoptera)

The Pajama Cardinalfish (Sphaeramia nematoptera) looks like three different fish stitched together and somehow works: a yellow face with a huge red eye, a hard black bar across the middle, and a rear half scattered with rust-red polka dots on silver. It hovers rather than swims, moves slowly and deliberately, and is one of the calmest fish you can put in a reef. It is also one of the very few marine fish that genuinely does better in a group. Browse the rest of our saltwater fish.

For a beginner reef it is close to ideal: hardy, undemanding, cheap enough to buy several, completely coral safe, and small enough for a 30 gallon. The one thing to understand before you buy is how slowly it eats, which is covered below.

Care Guide

• Tank size: 30 gallons and up for a small group. They barely swim, so rockwork and open hovering space matter more than length.
• Buy a group: three or more, added at the same time. They shoal naturally and a lone Pajama tends to hide. Groups spread out during the day and cluster together at night, which is half the appeal.
• Feeding, the important part: they are slow, deliberate feeders and will lose out to fast, greedy tankmates. Target feed with frozen mysis and enriched brine, and make sure food reaches them rather than being inhaled at the surface. This is the single most common reason a Pajama fails in an otherwise fine tank.
• Temperament: peaceful to the point of passive. They will not bother anything, including corals, clams, or ornamental shrimp.
• Water: 72 to 78°F, salinity 1.020 to 1.025, pH 8.1 to 8.4. Hardy and forgiving of ordinary reef conditions.
• Lighting and flow: they prefer moderate light and calm areas. Give them a low-flow pocket in the rockwork to hover in.
• Breeding: mouthbrooders. The male carries the eggs in his mouth and will not eat while brooding. They spawn readily in a settled tank, which makes them a good first project for anyone wanting to try marine breeding.

Specifications

Compatibility

Ideal alongside other calm reef fish: clownfish such as our Wyoming White, firefish, neon gobies, and its cousins the Banggai Cardinalfish and Longspine Cardinal. Safe with every invert and coral.

The real risk is not aggression, it is competition. Avoid fast, food-motivated tankmates like larger wrasses, aggressive damsels, and anthias that will clear the water column before a Pajama has decided to move. Also skip anything big enough to eat a three-inch fish: lionfish, groupers, large hawkfish, and triggers.

Recommended Foods & Supplies

• SFBB Frozen Mysis Shrimp, the staple they take most reliably
• Piscine Energetics 1 mm Saltwater Pellets once they are settled on prepared food
• Live Tigriopus Copepods to coax a shy new arrival into feeding
• Browse the full saltwater selection for tankmates and reef supplies

FAQ

What does "fresh out of QT" mean?
Every fish we bring in spends time in our in-store quarantine system before it reaches the sales floor. We watch it, treat preventatively, and confirm it is eating prepared food. These just graduated, so they are settled and feeding rather than straight off a shipping box.

How many should I get?
Three or more, bought at once. They are shoaling fish and a single one usually hides in the rockwork instead of hovering out front where you can enjoy it.

Mine is not eating. What now?
Almost always competition rather than illness. Target feed with frozen mysis using a turkey baster, feed after lights dim when the faster fish settle, and try live copepods to trigger interest.

Is it reef safe?
Completely. It will not touch corals, clams, or ornamental shrimp.

Why is it hardly moving?
That is normal. Pajamas hover in place for long stretches and become more active at dawn and dusk. Sluggishness is their personality, not a health problem.

Can I breed them?
Quite possibly. Males brood eggs in their mouth and pairs spawn readily in a settled tank. Rearing the fry takes live food and a separate tank, but getting them to spawn is the easy part.