The oyster toadfish, Opsanus tau, also known as the ugly toad, oyster cracker, oyster catcher, and bar dog, is a fish 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. In 1998, NASA sent the oyster toadfish into space to investigate the effects of microgravity on the development of otolithic organs. The study found little difference between terrestrial development and those in space.