I have 3 goniopora
started with a small Metalic green about half the size of a Gold ball, maybe a little wider
another green one size of a tennis ball closed, and when it opens its huge.
Then a red colony about 6+ inches.
I hardly ever feed them... i have strong lights and make sure they get Low/moderate flow and try to change the direction of the flow every few days.
I have had some brown jelly on my smallest one that literally ate the center of the Goni, I did a peroxide dip 2 times and that seemed to work. its been about 8 months since that happened.
When i say hardly ever feed, i mean literally... maybe 2 months will go by before i decide to give it a treat and use a baster to squirt some phyto over them with all power heads turned off. I honestly dont think they need it with good lights and good flow.
I wouldnt consider myself an expert at all on them, but i do have 3 of them.
I did have a small purple frag Goni, that didnt live long. It got the Brown jelly too and Dipping did not help it.
I have read in some places to make sure no air gets trapped in its skeleton. So with my current ones if i ever move them or remove them for a dip, when i enter them back in i make sure i rotate it all over to let the air out.
Just my experience with them.
I actually was thinking about trading my Red Goni, its in the trading live stock forum