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.
[2] The first publication was in the proceedings of the Linnean Society of New South Wales,[3] in which Count Castelnau gave his description with figures reproducing the sketches executed at the time by "a draughtsman" at Staiger's request.
[4] The components of the specimen were said by an anonymous confessor writing to the Sydney Morning Herald in 1930 to have been sourced from the tail of an eel, a mullet's body, and the head of an Australian lungfish.
The addition of a platypus bill, seemingly shown in profile in Castelnau's accompanying figure, is also reported in the letter revealing the hoax.
[6] In selecting the name of the genus, Castelnau says "In our present knowledge of this singular fish, some inconvenience might arise from giving it a significant name; and I think it is preferable to design it under the mysterious historical one of Ompax.