It's a 125 gallon. The system is very well established. It's had quite a bit of coral in it for a while now and loaded with copepods. All the fish went through Hypo for 10 weeks, plus 2 weeks of observation. They have been in the same tank for 3 weeks now. I have a pair of clowns, a niger trigger, naso tang, yellow tang, and a flame angel. The tang is pretty chill, but in QT he was with 2 other yellows and had to be separated due to bullying them. I chose to keep only 1 yellow for that reason and He doesn't mess with the other fish.