Hi Sarah,
The achilles is doing really well! He is eating pretty much everytime I look at him. He spends the day munching away at the seaweed that I clip on the side of the tank. Our powder blue and powder brown spend a lot of time chasing each other around. We're quite certain it's not aggression because one time, it will be powder blue chasing powder brown, another time it's the other way around. It's like they play Follow the Leader.
We finally managed to catch the foxface that was in the predator tank and we moved it to the 450. The two of them make a really impressive sight, swimming together for the length of the tank. Both of them are BIG! Probably around 8" each. I had to turn the lights out for the night though because it looked like they were starting to get aggressive towards each other. It really surprised me since they always seem to be the most docile fish there is. I'll see what they do in the morning when the lights come back on.