Merfolk, merpeople, mermaid and mermen. It's all the same in this situation
As many folklore will inform, a mermaid is an aquatic creature with the head and upper body of a human and the tail of a fish. Mermaids appear in the folklore of many cultures worldwide, including the Near East, Europe, Africa and Asia. The first stories appeared in ancient Assyria, in which the goddess Atargatis transformed herself into a mermaid out of shame for accidentally killing her human lover. Mermaids are sometimes associated with perilous events such as floods, storms, shipwrecks and drownings. In other folk traditions (or sometimes within the same tradition), they can be benevolent or beneficent, bestowing boons or falling in love with humans.
In all reality merfolk are essentially good in nature. They live in the underwater kingdom of Atlantis like most of the creatures of the sea. They are the one who are primarily accidentally discovered by the human race because they like to help the humans. They run Atlantis.
Unlike the common lore, mermaids can come in many different genders, sexuality's and colors
They can be female
They can be male
The merfolk also have developed special aspects, the most common speciality is wings. Now the wings have no actual function but these merfolk are seen as more beautiful and prestige and are more sought after for mating
Merfolk tails can come in a range of colors and styles, sometimes they look alike to common fish or sometimes they are unique and never seen before
Merfolk are very friendly, sociable and crave attention, they often come out into the open. A big goal for them is finding a mate and for merfolk that can either be another merperson or a human. Sexuality isn't a big thing for them
This can often lead to trouble and human capture...
Now some mermaids harbor mutations and they are often discriminated against if they don't add to the beauty. Some examples are
Discoloration of the skin and mutation of the facial skin
Discoloration of the skin, ripped fins and unfavorable hair and skin pairings. Mutated gills and skin markings
There are more but these are the most common. They are seen as untouchables
Now you know all you need to know about merfolk