How to Identify Cortez Damselfish

To identify Cortez Damselfish (Stegastes rectifraenum), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are typically dark brown to black, often with a yellowish or orange tint on the caudal fin and sometimes on the posterior body. Juveniles are often brighter, displaying iridescent blue spots or lines, particularly on the head and dorsal fin, which fade with age. Some individuals may exhibit a pale bar behind the pectoral fin.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Dark body coloration, often with a yellowish caudal fin., Robust, compressed body., Small, terminal mouth., Prominent scales.

Dorsal fin

Single dorsal fin with 12 spines and 14-16 soft rays.

Tail fin

Forked or emarginate caudal fin, often yellowish.

Pectoral fin

Rounded pectoral fins.

Distinctive fins

Anal fin with 2 spines and 12-14 soft rays. Pelvic fins are thoracic.

Identification Tips

1. 1

   Coloration

   Look for the dark brown to black body with a distinct yellowish or orange caudal fin in adults. Juveniles have iridescent blue markings.

2. 2

   Body Shape

   Its deep, compressed body is characteristic of damselfishes.

3. 3

   Behavior

   Observe its highly territorial nature, often seen aggressively defending a small patch of reef or algae.

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