Pajama Cardinalfish

Pajama Cardinalfish

Species:
Sphaeramia nematoptera
(sometimes listed as Sphaeramia orbicularis)

 

Common Names:
Pajama Cardinalfish, Polka Dot Cardinalfish

 

Origin:
Western Pacific (Indonesia, Papua New Guinea, Great Barrier Reef)

 

Adult Size:
~3 inches

 

Lifespan:
4–6 years with proper care

 

Appearance & Coloration

The Pajama Cardinalfish is one of the most charming and instantly recognizable reef fish in the hobby. It features a soft silver body accented by a bold black band running vertically behind the head, vibrant red to orange spots along the rear half of the body, and eye-catching yellow highlights on the dorsal fin. Its large eyes and rounded body give it a peaceful, almost cartoon-like appearance that adds personality to any reef aquarium.

 

Temperament & Behavior

Exceptionally peaceful and slow-moving, Pajama Cardinals are ideal for calm reef and community aquariums. They are non-aggressive and coexist well with other peaceful species. While they can be kept singly, they are most comfortable when kept in pairs or small groups, especially in larger systems. During the day, they tend to hover near rockwork and corals, becoming more active during feeding times and in lower light conditions.

 

Tank Size Requirements

• Minimum Tank Size: 30 gallons (single or pair)

• Recommended Tank Size: 50+ gallons for small groups

A well-structured aquascape with caves and shaded areas will help them feel secure.

 

Placement & Habitat

Prefers the mid-to-lower water column, often hovering near rockwork, branching corals, or overhangs. Pajama Cardinals appreciate a relaxed environment where they can remain visible without strong currents.

 

Lighting Requirements

• Lighting: Low to Moderate

They adapt well to bright reef lighting but benefit from shaded or dimmer zones.

 

Water Flow

• Flow: Low to Moderate

Avoid strong or chaotic flow, as these fish are not fast swimmers and prefer calmer water movement.

 

Diet & Feeding

Pajama Cardinalfish are carnivorous planktivores.

 

Diet Includes:

• Mysis shrimp

• Enriched brine shrimp

• Copepods

• Finely chopped seafood

• High-quality frozen and pellet foods

 

Feeding Frequency:
1–2 times daily. Most specimens adapt quickly to prepared foods once acclimated.

 

Reef Compatibility

• Reef Safe: Yes

Completely safe with corals, shrimp, snails, and other invertebrates.

 

Care Level

Easy

A hardy and beginner-friendly marine fish when housed in a peaceful, stable reef environment.

 

Compatibility Notes

Compatible with other gentle reef fish such as clownfish, gobies, blennies, firefish, dartfish, and small wrasses. Avoid aggressive or overly active tank mates that may cause stress or outcompete them for food.

 

Fun Fact

Like many cardinalfish, Pajama Cardinals are male mouthbrooders — the male carries fertilized eggs in his mouth until they hatch, releasing fully formed miniature fish.