The Collaborative International Dictionary of English v.0.48:
Toadfish \Toad"fish`\, n. (Zool.) (a) Any marine fish of the genus Batrachus, having a large, thick head and a wide mouth, and bearing some resemblance to a toad. The American species (Batrachus tau) is very common in shallow water. Called also oyster fish, and sapo. (b) The angler. (c) A swellfish. [1913 Webster]