How to Identify Pajama Cardinalfish

To identify Pajama Cardinalfish (Sphaeramia nematoptera), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The anterior half of the body, including the head, is bright yellow to greenish-yellow. A prominent, broad, dark vertical band (often black or dark brown) encircles the mid-body, extending from the dorsal fin to the anal fin. The posterior half of the body is silvery-white to light grey, densely covered with distinct, small, reddish-orange to dark red spots. The eyes are large and often have a reddish tint. The fins are generally translucent, sometimes with a yellowish or reddish hue.

Scale type

ctenoid

Mouth position

superior

Distinctive features

Bright yellow head and anterior body, Broad dark vertical band mid-body, Red-spotted posterior body, Large eyes, Elongated second dorsal fin spine

Dorsal fin

Two dorsal fins. The first dorsal fin has 6-8 spines, with the second spine often elongated and filamentous in adults. The second dorsal fin has 1 spine and 9-10 soft rays.

Tail fin

Caudal fin is forked.

Pectoral fin

Pectoral fins are relatively large and fan-shaped, with 12-14 rays.

Distinctive fins

Pelvic fins are thoracic, with 1 spine and 5 soft rays. Anal fin has 2 spines and 9-10 soft rays.

Identification Tips

1. 1

   Color Pattern

   The unique combination of a yellow head, dark mid-body band, and red-spotted tail is unmistakable. No other cardinalfish species shares this exact pattern.

2. 2

   Body Shape

   Laterally compressed, somewhat deep-bodied, typical of cardinalfishes, but the distinct color zones make it easy to identify.

3. 3

   Fin Spines

   Observe the elongated second spine of the first dorsal fin, which is particularly noticeable in mature individuals.

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