My sister-in-law has resolved to give me her 20g high tank that she is no longer using. I was thinking of starting a betta sorority! My question is, although I've been doing my research (planning on doing a fishless cycle and adding the females all at once) I'm not sure how many fish I can fit in a 20g high aquarium. I know that it is recommended to have an odd number of female betta. I was planning to get at least 7 females. What other tank mates can I safely include and how many fish can a 20g high aquarium hold? I want to use sand as a substrate so I was thinking of getting fish that sift sand in addition to the females. Any recommendations as far as stocking? I am not big on snails or shrimp.