How to Identify Dusky Chromis

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

Physical Characteristics

Body shape

compressed

Coloration

Distinctively bicolored. The anterior half of the body, including the head, is dark brown to black, while the posterior half, including the caudal peduncle and caudal fin, is stark white. The demarcation line between the two colors is sharp and typically runs vertically just behind the dorsal fin's soft ray origin. Some individuals may show a faint yellowish tinge on the white posterior section.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Sharp bicolored pattern (dark anterior, white posterior), Small, oval-shaped body, Forked caudal fin

Dorsal fin

Single dorsal fin with 12 spines and 12-13 soft rays. The spiny portion is continuous with the soft-rayed portion.

Tail fin

Deeply forked caudal fin, with pointed lobes.

Pectoral fin

Pectoral fins are clear to slightly dusky, moderately sized.

Distinctive fins

Pelvic fins are typically dark, matching the anterior body coloration.

Identification Tips

1. 1

   Coloration

   The most definitive identification feature is the sharp, vertical division of color: dark brown/black anteriorly and white posteriorly. No other Chromis species shares this exact bicolored pattern.

2. 2

   Body Shape

   Small, oval, and laterally compressed body, typical of many damselfishes.

3. 3

   Schooling Behavior

   Often seen in large, active schools hovering above coral heads, which is characteristic of the species.

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