I have two Rosy Barbs in my 80 liter tank. I have no problem with them. They are very peaceful. I think that if we put them together, they will not attack the other fish!
I have five Rosy Barbs in addition to some different Tetras. The Rosy Barbs are my favorite. They are so beautiful and playful and (in my tank) very peaceful, spending hours riding the current generated from my powerhead filter. They also don't spook during water changes like my Black Skirt Tetras.
I have 9 Rosy Barbs in my 40 liter community tank. They are a good beginner fish, and they will grow nice and plump if well fed. They feed top, middle and bottom, and will try and eat anything! I have 7 females and 2 males (by luck!), There is one dominant highly colored male. The otherīs color has not come out as much! They are not too aggressive when in a group, they have been known to have a nip at my Angelfish's fins, but that is rare. All in all, I would recommend them to anyone.
I have 3 Rosey barbs in a 100 L tank and they are so cool. The male is a longfin and he likes to play in the bubbles from my bubble wand. It looks like he is trying to take a shower, and even the 2 regular Roseys (1 female and 1 male) seem to enjoy watching him. They have been tank mates for over 2 years and will either ignore the sharks, or every once in a while they decide to try and chase them, but all it takes is for one of them to buck up and off they go...
I have a pair, male and female - The male was hard to get. Apparently in my area people buy up all the males who appear pale pink in the LFS and the females are left behind. The two are a riot. They scramble around my planted tank, cutting through the small school of tiger barbs in their frantic rounds. They are every bit as delightful and active as the tigers are. Unlike the tigers, the roseys seem to enjoy munching on the algae in the tank, judging by the poop color on some mornings. The male has developed a true rose-red color - very striking and follows the female around like a hopeful puppy, nudging her every so often. I've wondered about getting a second female so he doesn't drive the one mad with his attentions. He doesn't harm her - just never lets her be. They are peaceful, but very boisterous - not for a tank with shy fish.
I have kept Rosy Barbs in an unheated tank for many months now. They seem to be very happy. Currently it is winter, but my fish are having no problem with the colder temperatures. Granted I live in L.A., California so it does not get excessively cold here, but it is still rather nippy. I've read in many books that this species prefers cooler temperatures, below that of tropical tanks. In my opinion unheated tanks are the way to go with Rosy Barbs.