Tetrodotoxin (TTX, CAS Number [4368-28-9]) is a potent marine neurotoxin, named after the order of fish from which it is most commonly associated, the Tetraodontiformes (tetras-four and odontos-tooth), or the tetraodon pufferfish. (*snip*) The members of this order include the fahaka puffer (Tetraodon fahaka), the Congo puffer (Tetraodon miurus), and the giant mbu puffer (Tetraodon mbu). Pufferfish from the genus Fugu (F. flavidus, F. poecilonotus, and F. niphobles), Arothron (A. nigropunctatus), Chelonodon (Chelonodon spp.), and Takifugu (Takifugu rubripes) also store TTX and related analogs in their tissues.
Other marine organisms have been found to store TTX and include the Australian blue-ringed octopus (Hapaloclaena maculosa, uses TTX as a toxin for capturing prey), parrotfish, triggerfish, goby, angelfish, cod, boxfish (Ostracion spp.), tobies, porcupine fish, molas or ocean sunfish, globefish, seastars, starfish (Astropecten scoparius), xanthid crabs (Eriphia spp.), a horseshoe crab (Carcinoscorpius rotundicauda), two Philippine crabs (Zosimus aeneus and Atergatis floridus), a number of marine snails, flatworms, sea squirts, ribbonworms and arrowworms (which both use TTX as a venom for prey), molluscs (Nassarius spp. and the Japanese trumpet shell "Boshubora"), and marine algae (Jania spp.). Terrestrial organisms include the Harlequin frogs (Atelopus spp.), Costa Rican frog (Atelopus chiriquiensis), three species of California newt Taricha spp., and members of the Salamandridae (Salamanders). The number of species continues to grow.