I am starting a nano tank with Scarlett badis, crocidile toothpicks, and red cherry shrimp as my focus. However I wanted a schooling fish also. I was thinking a school of glass catfish. Compatable? I am open to other suggestions but preferably not a red fish. Also I have a 20 gallon and was considering upgrading my filter to a fluval c3. Anyone with expierience with this filter?