Planetary-mass natural satellites have the potential to be habitable as well. However, these bodies need to fulfill additional parameters, in particular being located within the circumplanetary habitable zones of their host planets. More specifically, moons need to be far enough from their host giant planets that they are not transformed by tidal heating into volcanic worlds like Io, but must remain within the Hill radius of the planet so that they are not pulled out of the orbit of their host planet. Red dwarfs that have masses less than 20% of that of the Sun cannot have habitable moons around giant planets, as the small size of the circumstellar habitable zone would put a habitable moon so close to the star that it would be stripped from its host planet. In such a system, a moon close enough to its host planet to maintain its orbit would have tidal heating so intense as to eliminate any prospects of habitability.