The oyster toadfish, Opsanus tau, also known as the ugly toad, oyster cracker and "bar dog", is a fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 of the family Batrachoididae. The maximum length of the toadfish is about 38 cm; the most common recorded length of an oyster toadfish is about 30 cm. They are generally yellowish with a pattern of brown oblique bars.

The species can live in very bad conditions and needs little food to live.