Triacanthidae

Triacanthidae, commonly known as triplespines or tripodfishes, is a family of Indo-Pacific fishes. It is classified in the order Tetraodontiformes, along with the pufferfishes and the ocean sunfish. The family consists of seven species in four genera, in addition to three extinct genera that are only known from fossils.

Much like their relatives the triggerfish and the filefish, the triplespines's first ray of the dorsal fin is formed to a spine. Further, they have two spines in place of their ventral fins. They have sharp and heavy teeth, which they use to eat hard-shelled molluscs and crustaceans.

Not much is known about how the fish live. They are essentially offshore fish that only come close to land occasionally. They range from 15 to 30 cm in length.

Fossil record
The genus Acanthopleurus is known from the species A. serratus Agassiz, 1844 and A. collettei Tyler, 1980 of the Oligocene of Glarus canton, Switzerland. A third described species Cephalacanthus trispinosus Ciobanu, 1977 from the Oligocene of Romania, formerly in the family Dactylopteridae, has been considered to be a juvenile specimen of Acanthopleurus, though whether it belongs with one of the two described species or a new species is not yet determined. Other fossil triplespine genera include Cryptobalistes, also from Glarus, as well as Protacanthodes from Monte Bolca, Italy.