I've found through my own situations that they do best in a tank that's at least 30" wide by 12" deep, with lots of places to hide.
If you're trying to spawn them, let them do so in a nice big tank, then remove the eggs and put them in a cycled 5+ gallon tank in a net placed under the filter outlet. Once the eggs start to hatch you can just then release them into that tank which is now your fry tank. It should have a sand substrate and some cover.