aqua"boy' (fr. Latin aqua-, water, + boy).
In circuses and sideshows, the guy with flippers for arms and legs is often put in a tank of water and called "Aquaboy". This sort of birth defect used to be called "dolphinism".
In the DC Comics Universe, Aquaboy is the teenaged equivalent to Aquaman, King of Atlantis.
In Katherine Dunn's book, Geek Love (about circus geeks, not computer geeks) Arturo, the aquaboy is the bitter, angry and ambitious antagonist who takes over the family buiness (a freak show). He rule his family with an iron fist, is psychically raped and impregnates his sister (it was his sperm, but there was no actual sex involved) and then gets blown up with his brother.