[smokinreefer]

i will speak of my experiences only...

i had a 135, though mine was 24" wide and 18"tall, reeftank with lots of rock... i had a yellow, a similar sized red sea sailfin, and a smaller purple... the purple was healthy but otherwise very timid, due to the aggresiveness of the larger yellow... the yellow and red sea sailfin were fine together, though those 2 were about the same size... or i should say, the red sea sailfin, grew to the same size of the yellow! (the red sea sailfin and red sea purple were added at the same time, same size, the sailfin quickly put on size, while the purple did not, was still fat, just didnt gain the size)

i now have a 180, and still have the red sea purple... i have since added a slightly larger powder blue tang, and both are getting along fine. keep in mind these are different species though.

HTH