About Rhinecanthus rectangulus (Bloch & Schneider, 1801)
Second Dorsal Spine
This species, commonly known as the reef triggerfish, has a small second dorsal spine. This spine is used to lock the fish’s main spine in an upright position.
Locking Mechanism Function
When the fish shelters in a small crevice, this locking mechanism prevents predators from pulling the fish out of its hiding spot.
Head Morphology
The reef triggerfish has a distinctly large snout and blue lips that resemble a pig’s snout. It has a terminal mouth and strong teeth, which help it scrape food from surfaces.
Body Coloration
The dorsal side and anterior end of the fish are orange-brown, and its belly is white.
Fin Ray Counts
Reef triggerfish have 3 dorsal spines, 22 to 25 dorsal rays, no anal spines, and 20 to 22 soft anal rays.
Fin Coloration
Their soft dorsal fins, anal fins, and pectoral fins are pale white, and their caudal fin is a cloudy, murky color.
Similar Species
The reef triggerfish is often confused with its two closest living relatives: the lagoon triggerfish and the picasso triggerfish.
