Fluid = either or both depending on the person at the moment
Super critical = ignores gender as a concept entirely in their self-definition; OR, considers themselves a gender that is based on different standards entirely, like certain religious positions in human cultures where a spiritual leader is considered to be neither/no gender
Don't fluids conform to the shape of their container? In a sense both fluid and gas would be conforming but solid wouldn't be because solids don't conform to the shape of their container.