I would have to disagree with those who call them boring. I was watching a group of about 25 in the aqaurium shop and they just looked stunning. In large group of small ones in a large tank would look great.
I must admit, Im not a fan of them in a group less than about 8 only because they seem a bit more jumpy and scard. I know some people would say 3 min, but I would defo build a group up to atleased 8.