I have Harlequin Rasboras in my 33 gal tank, along with one male Beta and some Otos'. I love the Harlequin Rasboras, because of their color, which is lovely when they are healthy! They are interesting to watch, due to the way they interact with one another in bumping off each other ect and they school both tightly and loosely depending on their mood. lol I also find them long lived and hardy and they never nip at other fish, which is one of the reasons I chose them to live with my Beta!