I have a 30 gallon with 1 angel, 1 gold gourami, 8 sterba cories, 1 rubbernose pleco. I wanted to add a school of 6-8 medium sized tetras (maybe congo tetras?) to give a little bit more activity in the mid range level of my tank. Do you think this would be pushing it? My tank isn't planted but I can plant it if that would help give the fish more territory to work with.