Plimpy

The Plimpy is a small round fish with two legs ending in webbed feet. It lives in deep lakes, and feeds on water snails. The Plimpy is not dangerous, but will nibble on the feet and clothing of unsuspecting swimmers.

Merpeople consider the Plimpy to be a pest, and they deal with it by tying its legs into a knot and letting it drift away.

When Harry Potter, Ron Weasley and Hermione Granger visited Xenophilius Lovegood in 1998, he covered the kidnapping of his daughter Luna by saying she was out fishing for plimpies near the Bottom Bridge.

Appearances
Boullu
 * Harry Potter and the Goblet of Fire
 * Harry Potter and the Deathly Hallows
 * Fantastic Beasts and Where to Find Them