@ TopazDiamond omg i didn't know they made mermaid tails, thats amazing! [side note: if using these tails is similar to the dolphin kick in swimming, you might want strengthen your legs and chore muscles first.]
sorry to burst your bubble, but real magick isn't like in faerie tales and the movies. real magick is more like a prayer. there is no sparks and things don't instantly appear, you are focusing energy to bring a desired change. this energy can only work within nature, and cannot go against it. you are human, so there is no spell to physically make you anything else. you could look into incorporating mermaids into your practice.