I'd have to agree with the comments on this site - best kept with a one male to 2 female ratio. The other male I had, when it was 1:1 ratio, was pecked to death and run in to some rock by the other male and never recovered. I think the other option of having a very large shoal is a great idea if you have the space in your tank.
I have 3 males and 3 females in my 250 L community tank. The pH is 7 and temp 26-27°C. They are one active little fish, but this doesn't seem to bother their tank mates. They are almost always together in a tight little group and it is not uncommon to see them schooling with my neon, black neon and glow-lite tetras. I think you need at least a 90 cm tank to appreciate the way these guys move. They have been a great addition to my tank.
I have had 7 of these fish for over a year, all males, as I find the females less attractive both in shape and colour. I have seen few references to this fish that didn't advise keeping at least as many females as males, if not more, but I'm not sure why. My bachelors display to each other constantly, school happily, dine like a pack of sharks, and are just beautiful, so I don't think spawning is essential to their well-being. They live with a gourami, small tetras, loaches, rasboras and Amano shrimp. They are particularly fond of Hikari micro pellets. I would advise a tank of at least a metre in length to allow them room for swimming -- they are active and prone to bursts of speed. These fish have lots of personality and are entertaining to watch. Highly recommended.
I had four Neon Rainbowfish sharing a 110 liter tank with 1 African Clawed Frog, a pair of Convict Cichlids, a large Blue Gourami and a Sailfin Plec. I feed them flake food, freeze-dried tubifex worms, and frozen bloodworm once a week. They are very active little fish, with a lot of character, they all lived happily until my frog was about 5 months old and he decided that they would make an excellent meal. The next morning, when I went to feed my fish, they were all dead, ripped apart, and my frog was very fat. So if you decide to keep these fish, or any other small fish, don't keep them with African Clawed Frogs.
These pages have enough comments to give the reader a basic idea on the topic. Further comments are still very welcome (through the site's contact form) as long as they provide new and/or advanced information not yet discussed in the existing ones.