Mermaids & mythology

A mermaid is a creature of myths and legends that lives under the water like an aquatic creature that has the tail of a fish instead of legs but the torso, arms and head of a human. The name Mermaid comes from the word "mer" meaning "sea" in French. The male equivalent of a Mermaid is a Merman. Mermaids are mostly associated with being the most beautiful, benevolent, sacred creatures as linked with goddesses in mythology, and tales of them falling in love with humans like fisherman, but there are also stories told of them being monsters of the sea and they have been portrayed as ugly too as they have been linked with floods, storms, drownings and shipwrecks.

https://upload.wikimedia.org/wikipedia/commons/5/55/John_William_Waterhouse_A_Mermaid.jpg

One of the first stories of Mermaids to be told was one about the ancient Assyrian goddess Atargatis who was the chief goddess of classical Antiquity, transformed herself into a mermaid out of shame and punishment for accidentally killing her human lover who was a shepherd. She cast herself into the sea hoping to become a fish, but as she was so beautiful she couldn't simply become a fish, but instead only her bottom half became a fish and the top half remained a goddess. Atargatis is called Great Mother and Goddess of Fertility of the Earth and Water. Doves and fish were her sacred animals, the doves symbolise love and fish symbolise her being the fertility of the water. In Ascalon, her home in Syria no one ate fish from the lake near her temple out of respect, it is said these fish were as tame as pets when approached by people and had jewels on their heads.The story of Atargatis spread from Assyria to Rome and Greece and is said to have influenced the worship of the Greek goddess Aphrodite.

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http://agreekisland.com/wp-content/uploads/2013/12/aphrodite-botticelli-.jpg

In Harry Potter they portray the Merpeople as the ugly, montrous type of mermaids which are cruel, evil and not pleasing to the eye. Not the kind of mermaids portrayed in childrens tales or that are often painted off. 

http://vignette3.wikia.nocookie.net/harrypotter/images/4/4b/C.jpg/revision/latest?cb=20071224150938

http://img2.wikia.nocookie.net/__cb20091018034049/harrypotter/images/a/a4/One_of_the_Merpeople_of_Hogwarts_Lake_%28Concept_Artwork%29.jpg

 
References:
https://en.wikipedia.org/wiki/Mermaid
https://en.wikipedia.org/wiki/Atargatis
http://www.seathos.org/atargatis-the-first-mermaid/
http://myths.e2bn.org/mythsandlegends/origins532-a-mermaid-and-a-magic-comb.html