So likely dark matter is a different flavor of something already in the model. Dr. Mills' Hydrino theory presents hydrogen with the electron in a lower orbit that does not radiate as a candidate for dark matter. These states are stable like the ground state. Transition into or between hydrino states emit light in the UV or soft X-ray wavelengths that is not seen in optical telescopes.
Obligatory
https://xkcd.com/2035/