They are beautiful, peaceful fish and do best in a male/female pair or as said above, 2 females, 1 male. They need a large tank of at least 55 gallons IMO and if they pair off successfully, you will be rewarded with the male building a bubble nest. The mature male will have stunning colours of iridescent blue, purple and dark orange, with long fins. The female stays more of a silver colour with light orange on the anal fins. The only problem comes in when the male wants to mate with a female and she doesn't want to. This will cause him to chase her incessantly and she may become very timid and hide. Another potential issue(I've had this happen twice now with different sets of pearls) is once they become mature, they get scared very easily. For instance, when I walk by my tank, I have to make sure that I walk lightly. Otherwise, the two of them go shooting off in the tank in a panic. One time the male threw himself under the canopy and injured himself pretty badly. He healed but there is a constant concern for him doing it again. I have a 140 g planted tank so lots of room for them and plenty of hiding places but they still scare easily with sudden movements and vibration. Otherwise, they are out in the open and quite active.
I highly recommend them if a person had a large enough planted tank.