Illustration on page 495 of s:Curious Myths of the Middle Ages. Original description:

"Oannes and Dag-on (the fish On) are identical. According to an ancient fable preserved by Berosus, a creature half man and half fish came out of “that part of the Erythræan sea which borders upon Babylonia,” where he taught men the arts of life, “to construct cities, to found temples, to compile laws, and, in short, instructed them in all things that tend to soften manners and humanize their lives;” and he adds that a representation of this animal Oannes was preserved in his day. A figure of him sporting in the waves, and apparently blessing a fleet of vessels, was discovered in a marine piece of sculpture, by M. Botta, in the excavations of Khorsabad."