These are pretty and inexpensive little tetras; shown above is the rarer longfin variety.
Although they are sometimes relatively peaceful in some community tanks, depending on the batch you get, you may get some very nippy individuals (though in general, not quite as bad as the notorious tiger barb). As such, I wouldn't recommend these fish to people with long-finned fish, such as angels or bettas, in their tanks. People have had varying opinions on this species, as there appears to be some variation in their behavior. Overall, they are very easy to take care of (this and the Black Tetra are some of the hardiest tetras out there).
Like most tetras, they should be kept in a school of 4-6 minimum (this also encourages them to be less nippy).