They have these mixed in with assorted Damsels at the south end Petco for 4.99. I may have just never seen them before but I thought they were very unusual. Like all damsels I am sure they are aggressive but in a larger tank with lots of hiding places they would make a beautiful addition. I cant use photobook to post pictures any more so I just linked it off live aquaria.

http://www.liveaquaria.com/product/2563/?pcatid=2563