This is my rendition of one of a fictional race of sapient fish called the "Deep Ones" that appear in H.P. Lovecraft's novella The Shadow Over Innsmouth. In that story, the Deep Ones offer a small New England coastal town wealth in both jewelry and fish in exchange for the right to interbreed with its citizens, thereby conferring onto them their immortality and ability to live underwater. The results of this inter-species admixture is portrayed as a subject of horror for the narrating protagonist, which is of course in keeping with Lovecraft's unfortunately of-his-time views on "miscegenation".

I actually have recently drafted a short story featuring these creatures, but my version of them is much more malevolent toward humanity than Lovecraft's, abducting them for sacrifice to the "Great Old Ones" they venerate. The story is a simple tale about a Paleolithic African woman and her tame saber-toothed cat fending off a Deep One raid, with both already having a bad history with the creatures.