Tetraodontiformes (/ tɛtrə.ɒˈdɒntɪfɔːrmiːz /), also known as the Plectognathi, is an order of ray-finned fishes which includes the pufferfishes and related taxa.

tetraodontiform, (order Tetradontiformes), any member of a group of primarily tropical marine fishes that are closely related to the perciforms (the typical advanced spiny-rayed fishes) that evolved during the Eocene Period of the Cenozoic Era, about 50 million years ago. Included are the triggerfishes, puffers, filefishes, and porcupine fishes.

Many species have small prickles on the skin of their bellies. Their skin, entrails, and sometimes their flesh may contain tetraodotoxin, an anti-predation poison that is highly toxic. Porcupinefishes are large, elongate, robust, and somewhat boxlike, and they are capable of inflation. They have numerous spines along the body.

The tetraodontiforms are distinguished externally by a small gill opening restricted to a relatively short slit on the side of the head and a small mouth, usually equipped with massive teeth.

Tetraodontiformes, or pufferfish, are most significantly characterized by the beak-like four teeth – hence the name combining the Greek terms "tetra" for four and "odous" for tooth. [8] Each of the top and bottom arches is fused together with a visible midsagittal demarcation, which are used to break apart and consume small crustaceans .

The Tetraodontiformes are an order of highly derived ray-finned fish, also called the Plectognathi. Sometimes these are classified as a suborder of the order Perciformes. The Tetraodontiformes are represented by 10 extant families and at least 349 species overall; most are marine and dwell in and around tropical coral reefs, but a few species ...

The teleost order Tetraodontiformes is a cosmopolitan group of marine fishes made up of nine families, including such recognizable and divergent groups as the triggerfishes, (Balistidae), filefishes, (Monacanthidae), boxfishes, (Ostraciidae), pufferfishes, (Tetraodontidae and Diodontidae), and ocean sunfishes (Molidae). Tetraodontiform feeding ...

Pufferfishes and their relatives belong to the order Tetraodontiformes that contains 447 species in ten families. They primarily live in marine habitats from coasts and reefs to open pelagic waters and deep ocean, but some pufferfishes live in freshwater …

The most advanced bony fishes are in the order Tetraodontiformes, an almost entirely marine order of medium-sized fishes with thick, leathery skin and with scales often modified into spines or bony plates.

Taxonomy and phylogeny of Tetraodontiformes, a order of ray-finned fishes. Based on the Phylogenetic Fish Classification. Also includes species checklists, fossil calibrations, DNA sequences.