The toadfishes are a type of ray-finned fish normally found on the sand and mud bottoms of coastal waters worldwide, notable for somewhat broad heads and drab coloration reminiscent of terrestrial toads, as well as for the ability of some species to "sing" using their swim bladders. They are normally classified as the sole family Batrachoididae of the order Batrachoidiformes, and include about 70 species in 19 genera, among them the common oyster toadfish, Opsanus tau.
Toadfishes are usually scaleless, with eyes set high on large heads. Their mouths are also large, with both maxilla and premaxilla. The pelvic fins are forward of the pectoral fins, usually under the gills, and have one spine with several soft rays.
Almost all are marine, but Daector quadrizonatus and Thalassophryne amazonica are known from Colombia (Atrato River) and the Amazon River, respectively.
Toadfishes of the genus Porichthys, the midshipman fishes, have photophores and four lateral lines, while the Thalassophryninae are venomous, with a total of four hollow spines (two dorsal and one on each opercle) connecting to venom glands and capable of delivering a painful wound. That will mess you up.
- J.S. Nelson, Fishes of the World
- CBC Radio Quirks and Quarks show podcast segment on unique toad fish habits with links to primary sources.