This is a mudskipper who is being drawn here solely for the qualities of its bulbous, beautiful eyes.
The illustration is from page 453 of The Vertebrate Eye and Its Adaptive Radiation by Gordon L. Walls, which I was browsing on archive.org.
It’s a study of light, how the energy of light shapes the flesh of us creatures who sense it. I’m not really exaggerating by phrasing it like that. From the first chapter: “just as there would be no sound if a tree were to fall with no one to hear it, so also there would be no light in the physiological sense if there were no photoreceptor upon which it impinged. In this other sense light is a sensation, an experience in consciousness.”
Then we (through Mr. Walls) get into snakes and birds and, yes, fish who all stare out at us in different ways. Mudskippers, as we all know, are fish that venture out on land, crawling around on muddy banks and mangrove roots like some kind of longer-legged land animal. This image illustrates a short section on “fishes which spend enough time out of water to have any possible use for air-and-water vision.”