I have three rocks of them in my tank, with multiple separated colonies on each rock. The rock with high, turbulent flow looks the fullest and spreads well. Another in gentle turbulent flow doesn't extend as much but also spreads well. The one in moderate, more linear flow does the worst, some colonies are somewhat stunted, and they have not spread much. The differences may also have to do with other factors such as proximity to do with proximity to certain corals or height in the tank. Anthelia's so hardy, it'll do pretty well anywhere.