Merperson

Merpeople are sentient beings (or beasts, as they want nothing to do with the likes of vampires and hags) that live underwater, and are found all over the world. Their customs and habits are mysterious, and, like the Centaurs, they refused Being status in favour of Beast. Merpeople can breathe above the waves for a time, but it is unclear if they can ever truly leave their habitat.Merpeople society is based around organised communities, and they have a great love of music. Their language is known as Mermish, and only a few Wizards know how to speak it. However, since their language can only be heard properly underwater, it sounds like a loud screeching when spoken above water. The merpeople of Hogwarts have greyish skin and long, wild, dark green hair. Their eyes are yellow, as are their broken teeth, and they wear thick ropes of pebbles around their necks. Their powerful, silver fish tails allow them to swim expertly, while the upper parts of their bodies resemble those of humans. Merpeople are also very tall, and during the second task, Harry encountered one in the lake near Hogwarts who was seven feet tall with a long green beard and a choker of shark fangs, carrying a spear. They have been known to keep Grindylows as pets, and use Lobalugs  as weapons. One tribe even managed to capture and domesticate a Hippocampus. Dolores Umbridge once requested the Ministry to have Merpeople rounded up and tagged, due to her hatred to half-breeds, though Merpeople are in fact a separate species of their own, not a mixed species between fish and human. Regardless of Umbridge's misunderstandings and hatred, this suggestion was never put into practice.