Ompax spatuloides was a hoax fish "discovered" in Australia in August, 1872. Said to be poisonous, it could be found on some lists of Australian fishes through the 1930s.
The fish was a joke perpetrated by people at Gayndah station, Queensland, who prepared it from the body of a mullet, the tail of an eel and the head of a platypus or needlefish. They served it cooked for Karl Theodor Staiger, the director of the Brisbane Museum, and he forwarded a sketch and description of the fake to expert Francis de Laporte de Castelnau, who described the supposed "species" in 1879.