tripterygiids

Tripterygiids, or triplefins, are a family of small, benthic marine fishes in the order Blenniiformes. They are notable for having three distinct dorsal fins along the back and an elongated body.

Most species are only a few centimeters long; sizes range roughly from 2 to 6 cm, with some up to about 8 cm. Coloration is cryptic, helping conceal them among algae and rocks.

They inhabit shallow coastal habitats such as rocky shores, kelp forests, and coral reefs. They occur in warm-temperate to tropical seas worldwide, with the greatest diversity in the Indo-Pacific.

Tripterygiids are ambush or active foragers, feeding on small invertebrates including crustaceans and mollusks, and in some species on algae. They are primarily benthic, spending much time in crevices and under overhangs.

Reproduction is oviparous. Eggs are laid on rock, kelp, or other substrates and guarded by males until hatching. Larvae are pelagic before settling to the reef or shore.

The family includes several genera, such as Tripterygion, Enneapterygius, and Forsterygion, among others. Their defining traits—three dorsal fins, slender bodies, and shore-associated habits—distinguish them from other blennioid fishes.

Conservation status is generally stable for widespread species, but localized declines can occur due to habitat degradation and pollution in coastal areas.