some bbgs are bw and need to stay that way but apparently theres a strain of fw that have been appearing in lfs latley. dixaisy930 thinks you might be able to tell a difference in the stripes, the the bw are brokenup and the fw are solid. check around and see what you find in the shops, they may only sell the bw type (my one lfs only sells the bw and puts a big sign on the tank that they are bw only)
and remember, there is no such thing as too many tanks