How to Identify Blue Parrotfish

To identify Blue Parrotfish (Scarus coeruleus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Juveniles are typically dark blue with a yellow spot on the head and a yellow caudal fin. Subadults transition to a more uniform blue. Adults are a vibrant, uniform blue, often with lighter blue or greenish hues on the head and fins. Large males may develop a prominent nuchal hump (forehead bump).

Scale type

cycloid

Mouth position

terminal

Distinctive features

Beak-like mouth formed by fused teeth, Large, prominent scales, Uniform vibrant blue coloration in adults, Terminal mouth, Large, fleshy lips

Dorsal fin

Single dorsal fin with 9 spines and 10 soft rays.

Tail fin

Slightly emarginate to truncate caudal fin in juveniles and subadults, becoming more rounded or slightly convex in large adults.

Pectoral fin

Large and fan-like, used for propulsion.

Distinctive fins

All fins are typically blue, matching the body coloration.

Identification Tips

1. 1

   Coloration

   Adults are almost entirely a brilliant, uniform blue. Juveniles have a distinct yellow spot on the head and a yellow caudal fin.

2. 2

   Mouth Structure

   The fused teeth forming a prominent 'beak' are characteristic of all parrotfish, but in S. coeruleus, it is particularly robust.

3. 3

   Size

   Can grow quite large, up to 1.2 meters (4 feet) in length, making it one of the largest parrotfish species.

4. 4

   Nuchal Hump

   Large adult males often develop a noticeable fatty hump on their forehead.

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