Ichthyocentaurus, Ichthyocentaur
That is, a fish-centaur, or a particular kind of Triton. Ichthyocentauri were fabulous beings, the upper part of whose body was conceived to have a human form, and the lower that of a fish, while the place of the hands was occupied by a horse's feet. They differed from the ordinary Tritons by the fact that the latter were simply half men and half fish, and had not the feet of horses. (Tzetzes on Lycophron)
From Smith's Dictionary of Greek and Roman Biography and Mythology