How to Identify Blue Reef Chromis

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

Physical Characteristics

Body shape

compressed

Coloration

Brilliant iridescent blue over most of the body, often with a darker, sometimes black, caudal fin and posterior dorsal and anal fins. Juveniles may exhibit a more uniform blue. The intensity of the blue can vary with mood and lighting.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Vibrant iridescent blue body coloration, Forked caudal fin, often dark or black, Small, oval-shaped body

Dorsal fin

Single dorsal fin with 12 spines and 12-13 soft rays. The soft-rayed portion is typically dark.

Tail fin

Deeply forked caudal fin, often black or dark blue, contrasting with the body.

Pectoral fin

Transparent to light blue, relatively small.

Distinctive fins

The dark caudal fin and posterior soft rays of the dorsal and anal fins are key distinguishing features.

Identification Tips

1. 1

   Coloration

   Look for the distinctive brilliant iridescent blue body. This is the primary identifier.

2. 2

   Caudal Fin

   Observe the deeply forked caudal fin, which is typically dark blue to black, providing a strong contrast to the body color.

3. 3

   Schooling Behavior

   Chromis cyanea are almost always seen in large, active schools hovering above the reef, feeding on plankton.

4. 4

   Size

   Adults typically reach a maximum length of about 10-13 cm (4-5 inches).

Explore Blue Reef Chromis