Aluterus scriptus (Osbeck, 1765)

Size

Aluterus scriptus is a medium-sized fish that can reach a maximum length of 110 cm (3.6 ft).

Body Shape

Its body is shaped like an elongated oval, and is strongly compressed laterally.

Base Coloration

The base body color is either olive-brown or grey, and this shifts to match the fish’s surrounding environment.

Body Markings

Irregular blue lines and spots are scattered across the body, with additional black spots that are concentrated mostly on the head.

Color Change Ability

Similar to octopuses, this species can change its color very quickly to match its background.

Observed Color Change Behavior

Individuals observed in the Virgin Islands have been recorded lying flat on sand and turning completely pure white, or changing to other matching colors.

Mouth and Snout

The mouth is small, positioned at the tip of the fish’s pointed snout.

Pelvic Fin Absence

Like all members of the order Tetraodontiformes, Aluterus scriptus lacks pelvic fins.

First Dorsal Spine

It has two distinct dorsal spines: the first, anterior spine is long, slender, and erectile, and sits just above the eyes.

Second Dorsal Spine

The second spine is small and not easily visible, but it locks the first spine in place when the first is erected.

Caudal Fin Structure

The rounded caudal fin is fairly long, and can be extended into a fan shape.

Juvenile Coloration

Juvenile Aluterus scriptus have yellow bodies marked with black spots.

Species Distribution

This species has a circumtropical distribution, and is found in tropical waters across the Atlantic Ocean, Indian Ocean, and Pacific Ocean.

Habitat

This filefish inhabits lagoons, coral and rocky reefs, seaweed fields, pinnacles, wrecks, and open water.