Hey guys first post here! This forum popped up everytime I google-fu'd a question and everyone seemed so helpful I decided to make an account. So I have a 20 gallon high planted with a sand substrate running on a large sponge filter hooked to a Tetra 40 air pump. I currently have 10 pygmy cories in there and want to add more fish. Would it be overstocking if I added 4-6 albino cories and possibly either a betta or a dwarf gourami? Thanks.