What I have noticed is that many of the orange color in the Aussie Acans do not like a lot of light. The orange seems to be what makes some of them so desirable. If you notice in peoples pic's these Acans with orange in them, most of the time only a few polyps have that orange coral, and they are usually side or end polyps that did not get as much light as the main colony. I've noticed E-tailers tend to show those couple of polyps in their close up pic's, but then when you see the whole colony, it's not as evident.
Anyway, if your Acans have that color in them, it's best to keep them under lower lighting. I thought maybe temperature was playing a role in making these loose color, but since I started collecting them in May, all of my Aussie Acans have been in water temps that had a daily range of 78F to 83F, and on really hot days 84F. This swing has made many other corals in the same system unhappy, yet the Aussie Acans I have look great. I have noticed a slight color change, but nothing like what others are experiencing. I'll have to get some updated pictures of my collection and compare them to older pics.
As for pink colors, I've noticed more lighting tends to bring out a more intense pink. I've experimented with one colony, cutting it in half, and keeping one half in almost complete shade, and the other was put under 400w halides in a shallow tank. The piece that was in the shade stayed the same color as when it came in. A light purplish. The other piece turned bright hot pink. It took about a month to color up.
So in my opinion, lighting has a lot to do with why these Acans are changing. They seem to look best under bluer lighting. And the blue 460nm pc bulbs make them really glow.
One other thing I do with my Acans is feed them regularly. Not sure if this helps them keep their color, but I bet it helps them grow, and look puffy. Some of the growth I've seen on my pieces I got in May is Just amazing.
