Merpeople are magical creatures that resemble humans from the waist up and fish from the waist down.
|“||Merpeople have greyish skin, long, wild, dark green hair, silver tails and yellow eyes and teeth.||”|
These creatures live at the bottom of the Great Lake in Harry Potter and the Goblet of Fire, and were part of the Second Task of the Triwizard Tournament; the four champions were required to rescue friends who had been kidnapped from them and tied at the bottom of the lake. According to this picture, we can say that there is a very large population of merpeoples in The Great Lake. And it's look like they have a great civilization.
Viktor Krum half-Transfigured himself into a shark and took Hermione Granger from the rock; Cedric Diggory used a Bubble-Head Charm to rescue Cho Chang. Fleur Delacour was attacked by Grindylows and was forced to retire prematurely, leading Harry Potter to save Ron Weasley and Gabrielle Delacour, Fleur's sister and hostage.
This event was portrayed in the moment Merpeople in Book 4 on Pottermore.
From the Story
Discovered in chapter 26, The Second Task
|“|| There is a colony of merpeople who reside in a mer-version of a village in the lake at Hogwarts. They live in crude stone dwellings stained with algae in the lake; many have gardens of weed around their homes, and one home has a pet Grindylow tied to a stake outside the door.
As Harry swims past them, many of the merpeople emerge from their homes to watch him, spears clutched in their hands. A crowd of merpeople float in front of the line of houses in the mer-village square. A choir of merpeople sing the song from the egg in the middle of the square, calling the Triwizard champions towards them, to a gigantic statue of a merperson hewn from a boulder. The merpeople refuse to help Harry free Ron, Hermione, Gabrielle and Cho, and won't allow Harry to borrow a spear from them. They swarm around Harry when he attempts to free Hermione from the statue, and tell him to only take his own hostage. The merpeople only leave Harry alone when threatened by his wand; they look scared as he points it towards them, as they know no magic, and scatter.
The Merchieftainess of the merpeople living in the lake is a particularly wild and ferocious-looking female. She tells Professor Dumbledore about the circumstances in the lake, explaining that although Harry was the last champion to return, he was the first to find the hostages, and was only delayed by his desire to save them all.