I have a few different types, a beautiful purple pagoda, some thriving suns, and a recently acquired duncan with 10 heads. I've had the duncan for about three weeks now, and while it eats greedily, it stays mostly shriveled. It shows no signs of bleaching; the color is still vivid, and no skeleton is showing. When it does poke out a few nubs, I can see it is in an area with it's desired level of strong but gentle turbulence. It is about 16" deep in my tank. Should I try to bring it up a bit?