How to Identify Pennant Bannerfish

To identify Pennant Bannerfish (Heniochus acuminatus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Predominantly white with two broad, diagonal black bands. The first black band runs from the anterior part of the dorsal fin through the eye to the pelvic fin. The second black band extends from the posterior part of the dorsal fin to the anal fin. The snout is typically yellow, and the caudal fin is yellow. The elongated fourth dorsal spine is white.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Greatly elongated fourth dorsal fin spine, forming a 'pennant' or 'banner'., Two prominent diagonal black bands on a white body., Yellow snout and caudal fin., Small, brush-like teeth.

Dorsal fin

11-12 spines, 23-25 soft rays; the fourth dorsal spine is greatly elongated, often exceeding the body length in adults.

Tail fin

Truncate to slightly emarginate, yellow in color.

Pectoral fin

17-18 rays, transparent to slightly yellowish.

Distinctive fins

Pelvic fins are black, contrasting with the white body.

Identification Tips

1. 1

   Elongated Dorsal Spine

   The most distinguishing feature is the extremely long, white fourth dorsal fin spine, which can be as long as the fish's body. This is a key differentiator from other similar-looking species.

2. 2

   Color Pattern

   Observe the two broad, diagonal black bands on a white body, with a yellow snout and caudal fin. The pelvic fins are also black.

3. 3

   Snout Shape

   The Pennant Bannerfish has a relatively short, pointed snout, unlike the longer, more tubular snout of some other butterflyfishes.

4. 4

   Schooling Behavior

   While often seen singly or in pairs, they can form large schools, especially juveniles, which is a characteristic behavior.

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