I set up my first FOWLR tank just at a year ago, prior to this I had always had freshwater and I finally wanted the beauty of a saltwater tank. The first 2 fish I introduced were a clown and a Blue hippo along with a CC starfish and a small red tipped hermit crab, followed that up with a clown and a Yellow tang and then added a coral banded shrimp, an orchid dottyback and finally a a fire shrimp. All of this is in a 46 gallon Bow front aqaurium with live sand and approx. 30 lbs of live rock with an emperor 400 filter (80 gallon) and a 75 gallon zoo-med canister filter. I have not had any fatalities nor any problems. My question is the blue and yellow are beginning to grow. When I bought them no one at the LFS told me how big they would eventually get. In fact, reading and researching I believe I am lucky they have survived this long! My blue tang wasn't even an inch long---about the size of a nickle and the yellow was just a bit bigger than that. Now they are both pushing 3-4 inches and I know I must get them into a bigger tank. So, due to my available space I am wanting to build my own aquarium 150 gallon but it would still be limited to 5 foot length and 2 foot width and 22 inches high. How soon do I need to do this since they appear to have acclimated fine at this time? Also I know they need to be able to swim will those dimentions allow for that? Thanks for any input.