Sorry, but that won't happen on this plane. You cannot physically alter your body in such a way. In all seriousness, you could find a mermaid costume(?) Or you can learn astral projection and learn to alter your spiritual body to take form of a mermaid. As well as change your looks in a lucidic dream.
there is a disease
Ichthyosis, fish scales - (ichthyosis) - congenital disease is often inherited, is detected in early childhood. The process reaches a maximum of 18 years and continues throughout life. The disease occurs without remission with little improvement in the warm season.
Symptoms. Ichthyosis is characterized by the appearance of scales on the skin, which becomes wrinkled, dry, gray, gradually covered with thick horn-shelled gray-brown color with deep cracks.
Predominantly affects the extensor surface of the skin of the extremities (especially the elbows and knees), and sacral region. Characterized by symmetrical lesions. The skin of palms and soles of different dry. Depending on the degree of education and type of horny scales, color, and dryness of the skin, the spread of the process are distinguished set of clinical forms of ichthyosis - from mild dryness (xerodermia, ichthyosis simplex) to severe forms (ichthyosis serpentina), resembling the scales of a snake or crocodile skin (ichthyosis hystrix) .
witches in my country knows black magic ritual. it the disease being transferred from one person to another person. One man gives his illness differently. A ichthyosis (fish scale) also bolez. and it can transfer from a sick person, another person who dreams to become a mermaid.
ichthyosis patients have to find and offer him to share with a healthy man, suffering and dreams of becoming a mermaid.
there are the volunteers?