I have 2 10g tanks, one 20-long tank, and one large deep r-maid. The tanks work great; no one can squeeze out between any bars like in cages, and the r-maid is working well too. I used it in a pinch when one of my tanks broke, and decided to keep it for my male and whatever female he has to breed.. put charcoal-grill grates on top weighed down by bricks and it works great! but 10-g tanks are the way to go.. get one for each female and a few spares, and lids, and weights, and yer all set.. ask around at pet stores for any that may be broken and therefore cheaper, though I can get brand new ones for a mere $5 at the LFS.