So far, I've had great luck feeding Grape Caluerpa to my Yellow Tang and my Foxface Lo. I have it growing in a 10 gallon "Pod" tank. I pull out clumps of it and rubberband it to the rocks in the display tanks. They LOVE it. I've been doing it for about 6 months now. Several people warned me away from doing it on the grounds that the Caluerpa would take hold and over run my tank. So far, I've not seen a sign of it anywhere in the tank, other than where I put it to feed. A feed a clump that's about half the size of my fist about every 4 days. It's always gone in 2 days. The other day I did see my Turbo Snail munchin' on it as well. When I started this process, I watched both fish to make sure they were eating it. At first, they ignored it...then started nibbling after about a week. Now they devour it!! So far, it's growing faster in my "pod" tank than I'm feeding it so it's a ready food supply. BTW, this is in 2 different tanks and I've still not seen any Caleurpa growing in either tank.