There's a lot of different opinions on how these guys should be kept. I commonly hear of them in 10 and 20 gal tanks. I thought about them for my 29 but decided to wait. I wouldn't keep them in a group of less than six, and I just felt like six potentially over 4" fish wouldn't have adequate space in a 29. I don't know though, I haven't owned them yet, and sometimes first hand experience changes your opinion.