Beautiful fish, actually Bororas Brigittae is the correct scientific name, commonly known as the Chilli Rasbora, or the Mosquito Rasbora.
As with all rasboras, the more the merrier, but no fewer than 6 in the group. I found them to shoal very loosely, much less than say cardinal tetras or CPDs. They prefer lower pH and softwater, although I've had them in my pH7.8 hardwater without problem. They are a very shy species, that needs heavy planting and lowish light to feel comfortable - with heavy planting, they know there is somewhere they can hide if necessary, so they are more likely to be out and about in the open sections of the tank. With no cover, they will just hide behind the heater or at back corners.
They are easy to feed, but because of their small size you may need to break up the flakes. I used to feed mine on Sera Vipagran fry granules, which they took quite happily.
Since they are quite shy, they should only be kept with other peaceful tankmates, otherwise they may well be out-competed for food. They are an ideal shoaling mid-water species for nano-tanks (mine were in a 34l).
They aren't the easiest to breed, they are egg-scatterers, so in a community setting, either they or their tankmates will usually eat all the eggs, although with some java moss, you may be lucky to get the odd one or two fry. In a specialist breeding tank, allowing the eggs to fall down into a substrate of marbles, such that the adults can't get to the eggs, you would get some success.
Hope this answers all your questions.