I'm not sure you need to feed it anything other then light and good water quality. It does pack a punch from all I ever read about it. I had a piece at one point but kept it isolated, or away from the nice stuff.
It packs more than a punch... a bomb is more like it. It doesn't really "sting" things often with, say, sweeper tentacles. What it does do is send out mesenterial filaments to digest its neighbors--and a LOT of them.
"When they was no meat we ate fowl, when there was no fowl we ate crawdad. And when there was no crawdad to be found, we ate sand."--Cellmate
"You ate what?"--H.I.
"We ate sand."--Cellmate
"You ate sand?"--H.I.
"That's right."--Cellmate
I'm sure it is a Hydnophora either a rigida or grandis. Good luck with it. Some people have great success and need to trim them regularly others don't grow or die and some just die. Mine belongs in the middle category. I have had it for three years and it is not grown at all. It has receded some but that is due to the crab and gobie mafia. the crabs knock it aff and the gobies cover it with sand. I hope that when I change tanks something changes and it starts to grow because they can be beautiful corals when they grow to a good size.
My Hydnophora got killed off by pods, then I got a CBS to keep my pod population in check, and the SPS came back, but it doesnt look like the first pic when I first got the frag. Anyway its on a comeback.