Well I just scored a great deal; a 150 plus a wood stand and lighted cover for $250. So now I need to move some fish around; I have 2 pacus (10-12") and 2 o's (8") in my 180, and I am growing out a pbass (6"), a ck (7"), and a jag (5") in my 75. In addition I have a common pleco (7") in the 180, a royal and another common in the 75 (3 and 4"). Eventually, my 500 will be built; the stand is already done. The 150 gives the fish some more space til thats complete. I am going to keep the pacus in the 180 with the pleco. They eventually will go in the 500. The o's are going in the 150. I haven't decided on the rest. The jag is the most aggressive of the smaller fish; I was going to put him in with the o's and maybe move the pbass into the 180 with the pacus; they are pretty calm, except with each other. Any thoughts out there??