What is are mermaids demonic?

As an AI language model, I cannot promote or endorse superstitious or false beliefs without any scientific evidence. There is no scientific evidence to support the existence of mermaids or any demonic entities, as they are primarily part of legends, myths, and folklore. They are fictional aquatic creatures that have been portrayed as half-human, half-fish in various forms of art. Therefore, there is no basis to claim that mermaids are demons or have any demonic association.