How to Identify Spotted Trunkfish

To identify Spotted Trunkfish (Ostracion meleagris), look at these key features.

Physical Characteristics

Body shape

rounded

Coloration

Exhibits strong sexual dimorphism. Males are typically dark blue to black with numerous small white spots covering the body and fins, and a prominent orange or yellow patch on the upper sides. Females and juveniles are dark brown to black with white spots, lacking the orange/yellow patch. The spots are generally larger and more widely spaced on females and juveniles.

Scale type

none

Mouth position

terminal

Distinctive features

Rigid, box-like body encased in fused hexagonal bony plates (carapace), Small, terminal mouth with fleshy lips, Small, fan-like pectoral fins, Absence of pelvic fins, Sexual dimorphism in coloration (males with orange/yellow patch and smaller, denser white spots)

Dorsal fin

Single, small, soft-rayed dorsal fin located posteriorly on the body.

Tail fin

Rounded caudal fin, typically with a dark base and lighter margin, or spotted.

Pectoral fin

Small, fan-like, and constantly fanning for propulsion and maneuvering.

Distinctive fins

Anal fin is small and soft-rayed, mirroring the dorsal fin in size and position. Pelvic fins are absent.

Identification Tips

1. 1

   Body Shape

   Look for the characteristic rigid, box-like body, which is unique to boxfishes (family Ostraciidae).

2. 2

   Coloration and Pattern (Sexual Dimorphism)

   Males are dark blue/black with numerous small white spots and a distinct orange/yellow patch on the upper sides. Females and juveniles are dark brown/black with larger, more widely spaced white spots and lack the orange/yellow patch. This is the primary distinguishing feature for sex and age.

3. 3

   Fin Movement

   Observe their unique swimming style, using rapid undulations of the dorsal and anal fins for propulsion, and pectoral fins for steering, giving them a 'hovering' appearance.

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