The Hagfish, or Slime Eel, is said to be an aphrodisiac. Hard evidence that hagfish can enhance sexual prowess is lacking, but this fish can get evolutionary biologists very hot.
A recently published paper, reviewed here, on Pharyngula, addresses the interesting evolutionary question. In general terms, it is this: Hagfish possess traits that appear to be ancestral to vertebrates, but that in fact might be derived. Therefore, they are either a sister group to the living vertebrates, or are correctly placed within the vertebrates (i.e., with the lampreys). If the latter, it is correct (yet trivial and teleological) to say that hagfish are “more evolved” than many other vertebrates … when it comes to nostrils, image-capturing eyes, and some other traits, the hagfish says “I’ve been there, done that … but now since I live way at the bottom of the ocean, I don’t need those costly traits.”)
The aphrodisiac bit comes from a Korean custom. This is probably just a matter of symbolic consonance. Hagfish are penis like in shape, of enviable length (for a human penis) and produce copious quantities of slimy stuff when, for example, touched or stroked. Obviously they would be an aphrodisiac.
US based fisherman love hagfish. Lobstermen used to hate them because they are very unpleasant (because of the slime thing) when they get mixed up in the lobster trap. But now that they can be shipped off to East Asia for those Zany Korean men to purchase at premium price, hagfish are good. I remember being out on a lobster boat many years ago, in Maine, the Lobseterman pulling urchins out of his trap and throwing them in a bucket: “Time was, we’d toss these… Didn’t like ‘em one bit. But they pay a bundle in Japan for these things. They’re crazy, but you gotta love those [racist term deleted]…”
Here’s a picture I took of a hagfish at the Two Ocean’s Aquarium, in Cape Town:
Playing with Hagfish Slime:
Holy Slimewad, Batman!
Hagfish sliming around in what I presume to be a Korean Restaurant:
Other sources, discussions, etc. on the hagfish: