A submission for the Anatomically Correct Series.
The Vodník (or Vodyanoy) are very interesting water spirits from Slavic mythology.They're described to have long green hair, and a face like a frog. Their body is inevitably covered in algae and mud, since living in a swamp doesn’t afford the most hygienic of lifestyles, and he’s typically covered in black fish scales. He has large webbed paws instead of hands, a fish’s tail, and eyes that are said to burn like scorching hot coals.
In Czech, Slovenian, and Slovak accounts however, they essentially just look like regular men, with the exception of the gills, webbed hands, and algae-colored skin. But for the sake of this question, we're going to use both descriptions.
Let's say that they evolved closer from humans due to the three alternate accounts, and also have amphibian attributes due to the frog head and webbed paws. How can we realistically get as close as possible to a depiction of a Vodník? I'm willing to flex and go with the artistic depiction if that helps.