The Rosy Barb is a beautiful fish which has been developed into a number of various strains by the aquarium hobby. The most common of these (pictured) is the long finned rosy barb, which has significantly longer fins. A Neon Rosy Barb variety exists, which has brighter colours, as well as the Glass Barb, which has a more solid pattern, and several other less commonly encountered varieties. These are all the same fish, and can be maintained the same way.
Interestingly, this species shows incredible sexual dichromatism -- males and females are different colours. Males are bright red, while females are golden. Rosy Barbs are also a cool water species, and while they'll do just fine in our tropical aquariums, they'll also handle cooler weather as well (making them an interesting addition to a small outdoor pond, at least until winter). Rosy Barbs are a fantastic addition to a planted aquarium, where they will act as great algae eaters, eliminating thread, brush, and string algae. They do not damage plants.
Rosy barbs are peaceful, and shouldn't bother other fishes. They may be mixed with virtually any fish that poses no threat to the Rosy Barb.