How to Identify Lined Surgeonfish

To identify Lined Surgeonfish (Acanthurus lineatus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The body is predominantly yellow to yellowish-orange, adorned with numerous thin, horizontal, wavy, dark blue to black stripes that run from the head to the caudal fin. The dorsal, anal, and caudal fins are typically yellow with blue margins. The pectoral fins are clear to yellowish. A prominent black spot is often present at the base of the caudal fin, anterior to the caudal spine.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Sharp, retractable scalpel-like spine on each side of the caudal peduncle (tail base), Elongated, oval-shaped body, Small, terminal mouth with fine, comb-like teeth, Vibrant yellow body with numerous dark blue/black horizontal stripes

Dorsal fin

Single, long dorsal fin with 9 spines and 27-29 soft rays. The spiny and soft-rayed portions are continuous.

Tail fin

Lunate (crescent-shaped) caudal fin, often with elongated lobes in adults.

Pectoral fin

16-17 soft rays, relatively small and clear to yellowish.

Distinctive fins

Anal fin with 3 spines and 25-28 soft rays. Pelvic fins with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Coloration and Pattern

   Look for the distinctive yellow body with numerous thin, wavy, dark blue to black horizontal stripes. This pattern is unique among surgeonfish.

2. 2

   Caudal Spine

   Observe the sharp, retractable scalpel-like spine on each side of the caudal peduncle. This is a defining characteristic of all surgeonfish (Acanthuridae).

3. 3

   Habitat Preference

   Often seen in areas of strong surge and current on outer reef slopes, actively grazing on algae.

4. 4

   Behavior

   Its highly territorial and aggressive behavior, especially towards other herbivorous fish, can be a key identifier in its natural environment.

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