tetra valentini is a puffer fish fish person

she has multiple poison needles all over her body that she can pull out of her skin(her hair is a large mass of needles form into a hair style, and the purple spots are areas where the poison needles are more easily extracted out of from her skin)

she can also inflate her body freely using water or air to enlarge her body to look more humanoid or monstrous, depending on the moos(other denser stuff may not travel in her body as freely)

she's a very romantically active individual that falls for others easily and uses her body changing abilities to try and look as attractive as possible for her attempts at seduction