For what it's worth, I've got half a dozen adults and a few juveniles (they breed very quickly) in an 8 Imperial gallon (about 10 US gallon) aquarium with about a million red cherry shrimps and a huge clump of Java moss. It's one my favourite tanks and a lot of fun to watch. I don't go out of my way to breed the ricefish, but rescue the odd juvenile I find in a floating breeding trap until they're big enough to set loose with the adults.
Yes. The eggs take a good while to hatch (at least a week, I think) but the fry are big enough to eat Hikari First Bites as soon as they hatch, so rearing couldn't be easier!
Edit: Matt Ford over at SeriouslyFish reports that the Oryzias melastigma name may be invalid, and that the correct name for this species is Oryzias dancena. It's further mentioning that this species comes from a range of habitats including brackish waters. With this in mind, adding a little salt may be helpful if you have problems keeping or breeding this species.