Yup you dont need a skimmer. Anything under a 30 doesnt need a skimmer and any tank can run without one. They do help out alot with water quality but doing pwcs does the same. Obviously, as tank size gets bigger, its alot harder to do pwcs (I do 30-40g a week) and for the people with 500s, it pretty much needed. If you want, you could get a refugium. They are great too, and look cool. GL!!!!!