A mermaid is a mythological aquatic creature with a female human head, arms, and torso and the tail of a fish. A male version of a mermaid is known as a "merman" and in general both males and females are known as "merfolk
Todays - beautiful creatures that sing songs and live in the sea. Carefree and fun loving. 'The Little mermaid' by disney and The little mermaid books and the story of atlantis premotes this.
In ancient history -
The One Thousand and One Nights includes several tales featuring "Sea People", such as Djullanar the Sea-girl. Unlike the depiction in other mythologies, these are anatomically identical to land-bound humans, differing only in their ability to breathe and live underwater. They can (and do) interbreed with land humans, the children of such unions sharing in the ability to live underwater.
In another story it bears a resebalence to Atlantis - where a ancient civilisation got so advanced it destroyed itself and now lives underwater.
Mermaids were noted in British folklore as unlucky omens – both foretelling disaster and provoking it. Several variants of the ballad Sir Patrick Spens depict a mermaid speaking to the doomed ships; in some, she tells them they will never see land again, and in others, she claims they are near shore, which they are wise enough to know means the same thing. Mermaids can also be a sign of approaching rough weather.
Some mermaids were described as monstrous in size, up to 2,000 feet (610 m) Which is franckly just frignting given their negativity - also there is a sceane in Xena (worrior princess - yes I am a sci-fi geek) where Neptune comes out compleatly made of water and is about this high...
No idea why i like this so much - Mermaids have also been described as being able to swim up rivers to freshwater lakes. One day, in a lake near his house, the Laird of Lorntie went to aid a woman he thought drowning; a servant of his pulled him back, warning that it was a mermaid, and the mermaid screamed after that she would have killed him if it were not for his servant. - nope still caan't figure out why, maby its the irony?
On occasion, mermaids could be more beneficent, teaching humans cures for disease, but why they would have this knowlage I don't know.
Some tales raised the question of whether mermaids had immortal souls, answering in the negative. (poss where Hans Christian Andersen got this idea from???) The figure of Lí Ban appears as a sanctified mermaid, but she was a human being transformed into a mermaid; after three centuries, when Christianity had come to Ireland, she was baptized.
Mermen were noted as wilder and uglier than mermaids, and they were described as having little interest in humans - and for some reason nobody seems particulary interested in them... Maybe they perfer seaball or tailball and like their kelp beer better?
In some ancient fairy tales of China, the mermaid was a special creature whose tears could turn into priceless pearls. Mermaids could also weave an extremely valuable material, translucent and beautiful. Because of this, fishermen longed to catch them, but the mermaids' splendid singing could simply drag them down into a coma.
In other Chinese legends, the mermaid is wondrous, but brainless and easy to trap. The legend said that mermaids were born with purple tails that smelled of happiness, but if sadness or death occurred during the mermaids' lifetimes their tails would turn red, and smell like sadness. So fishermen longed to catch mermaids in order to sniff their purple or red tails.
Suvannamaccha (lit. golden mermaid) is a daughter of Ravana that appears in the Cambodian and Thai versions of the Indian Ramayana. She is a mermaid princess who tries to spoil Hanuman's plans to build a bridge to Lanka but falls in love with him instead. In Indian mythology, Matsya Avatar (Merman) is the first incarnation of Lord Vishnu, who has lower part of the body like a fish, and upper part like that of a man. He has four arms; with two hands he holds a conch shell and wheel, while the other two are holding a lotus or a mace.
So yeh mostly not something you'd want to come into contact with everyday... So why the hell did it change??? Nice storys that got watered down over time?