How to Identify Dusky Gregory

To identify Dusky Gregory (Stegastes nigricans), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are typically dark brown to black, often with a yellowish or pale caudal fin, especially in juveniles and subadults. Some individuals may exhibit a pale bar or patch on the flank. The intensity of coloration can vary with mood and environment.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Robust, deep body, Small, terminal mouth, Prominent eyes, Often a pale or yellowish caudal fin, particularly in younger individuals, Dark spot at the base of the pectoral fin

Dorsal fin

Single dorsal fin with 12 spines and 15-17 soft rays. The spiny and soft-rayed portions are continuous.

Tail fin

Forked or emarginate caudal fin, often yellowish.

Pectoral fin

Well-developed pectoral fins, typically clear or slightly dusky.

Distinctive fins

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

Identification Tips

1. 1

   Coloration

   Look for the overall dark brown to black body, often with a contrasting yellowish or pale caudal fin, especially in juveniles. The dark spot at the pectoral fin base is also a good indicator.

2. 2

   Body Shape

   Its deep, compressed body is characteristic of damselfishes, but its robust build helps distinguish it from more slender species.

3. 3

   Behavior

   Observe its highly territorial behavior, aggressively defending a patch of algae from other fish. This behavior is a strong clue to its identity.

4. 4

   Habitat

   Its strong association with live coral and rocky substrates in shallow reef environments is a key identification aid.

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