How to Identify Yellowtail Damselfish

To identify Yellowtail Damselfish (Chrysiptera parasema), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The body is an iridescent electric blue, transitioning sharply to a bright yellow caudal fin. The posterior portions of the dorsal and anal fins are also yellow, creating a distinct bicolored appearance. Some individuals may exhibit a slight yellow tint extending onto the posterior body, but the demarcation is typically very clear.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Vibrant electric blue body, Bright yellow caudal fin, Sharp demarcation between blue body and yellow fins

Dorsal fin

Single dorsal fin with 13 spines and 10-12 soft rays. The posterior soft-rayed portion is yellow.

Tail fin

Forked caudal fin, entirely bright yellow.

Pectoral fin

Transparent to slightly yellowish, typically 16-18 rays.

Distinctive fins

The striking contrast between the blue body and yellow caudal fin is the most distinctive feature.

Identification Tips

1. 1

   Coloration

   Look for the unmistakable electric blue body with a sharply contrasting bright yellow caudal fin. The yellow also extends to the posterior soft rays of the dorsal and anal fins.

2. 2

   Size

   Adults typically reach a maximum size of about 6-7 cm (2.4-2.8 inches) in total length.

3. 3

   Behavior

   Observe its behavior around coral branches; it will often dart in and out of cover. While generally active, it tends to stay close to its chosen shelter.

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