toadfish, common name for the sluggish, bottom-feeding fishes of the genus Opsanus, found in the shallow waters from New Jersey to the Caribbean. Toadfishes feed almost entirely on crustaceans and small fishes. The head of a toadfish is broad and flat, with barbels and fleshy fringes, sharp gill covers, and spiny protrusions on the cheeks; the mouth is enormous and has many sharp teeth. The scaleless, slimy body tapers to a slender tail. Toadfishes grow to 1 ft (30 cm) in length. The eggs, sometimes laid in empty shells or tin cans, are guarded viciously by the male. The midshipmen (Porichthys species) of the same family are deepwater fishes of the Atlantic and Pacific oceans, with many small luminescent organs on the underside of the body. Other members of the family are found in tropical waters and have venomous spines. Toadfishes and their relatives are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Batrachoidiformes, family Batrachoididae.

Any of about 45 species (family Batrachoididae) of heavy-bodied, carnivorous, bottom-living fishes, found chiefly in the New World and mostly in warm seas. Toadfishes, up to 16 in. (40 cm) long, have a broad, flattened head, a large mouth, strong teeth, and small scales (if any). Most produce grunting or croaking sounds. The oyster toadfish (Opsanus tau) is common in shallow eastern North American coastal waters. Venomous toadfishes (genera Thalassophryne and Daector), of Central and South America, have venom-injecting spines on their dorsal fins and gill covers. Midshipmen (genus Porichthys), shallow-water American fishes, have rows of 600–840 buttonlike light organs along the body.

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