How to Identify Black-faced Blenny

To identify Black-faced Blenny (Tripterygion delaisi), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Males in breeding season exhibit a striking black head and anterior body, contrasting with a reddish-orange to brown posterior body. The dorsal fins are often edged with blue or white. Females and non-breeding males are generally more cryptic, with mottled brown and reddish patterns, often with dark bars or spots along the flanks. The eyes are relatively large.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Three distinct dorsal fins, Large eyes, Sexual dimorphism in coloration, especially during breeding, Dark pigmentation on the head and anterior body (more prominent in males)

Dorsal fin

Three separate dorsal fins. The first dorsal fin has 3 spines, the second has 10-12 spines, and the third has 7-9 soft rays. The first two dorsal fins are often elevated in males during courtship.

Tail fin

Rounded caudal fin.

Pectoral fin

Large, fan-like pectoral fins with 13-15 rays, often used for perching on substrates.

Distinctive fins

Pelvic fins are jugular (located anterior to the pectoral fins) with 1 spine and 2 soft rays, often appearing filamentous.

Identification Tips

1. 1

   Dorsal Fins

   Look for the three distinct dorsal fins, a characteristic of the Tripterygiidae family. The first two are spiny, the third is soft-rayed.

2. 2

   Head Coloration (Males)

   Breeding males are unmistakable with their intense black head and anterior body, contrasting with a reddish-orange posterior. This is the most reliable field mark for males.

3. 3

   Habitat Preference

   Search in shaded rocky crevices, under ledges, or in caves in shallow coastal waters. Their cryptic coloration helps them blend in.

4. 4

   Body Shape and Size

   Small, elongated body, typically not exceeding 6 cm in total length.

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