How to Identify Chromis

To identify Chromis (Chromis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are typically dark brown to black, often with iridescent blue or purple hues, especially when observed in natural light. Juveniles are often brighter, exhibiting a more pronounced blue or bluish-green coloration. The fins are generally darker, matching the body color.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Deeply forked caudal fin, Small, terminal mouth, Relatively large eyes, Continuous dorsal fin with 13-14 spines and 10-12 soft rays, Anal fin with 2 spines and 9-11 soft rays

Dorsal fin

Single, continuous dorsal fin with a spiny anterior portion and a soft-rayed posterior portion. Typically XIII-XIV, 10-12.

Tail fin

Deeply forked, with pointed lobes.

Pectoral fin

Well-developed, rounded, and used for maneuvering.

Distinctive fins

Pelvic fins are thoracic, located directly below the pectoral fins.

Identification Tips

1. 1

   Body Coloration

   Adults are typically dark brown to black with iridescent blue or purple sheen. Juveniles are often bright blue.

2. 2

   Caudal Fin

   Distinctly and deeply forked, a key characteristic for identification.

3. 3

   Schooling Behavior

   Often observed in large, active schools in the water column above reefs.

4. 4

   Size

   Reaches a maximum total length of about 25 cm (10 inches), but more commonly observed around 10-15 cm (4-6 inches).

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