woaw, that's a very good shot, Broog! and I love the name too!
You are very lucky to have had yours coming with the rocks! I have 3, but I had to buy them. Actually, i bought one, and as I was seing him about once every 10 days, I added 2 others to have the chance to see them more! And now, I see them everyday, and two are a couple now. I observed one of them carrying eggs, a beautiful neon orange belly, but didn"t have the opportunity to catch this on photo, the crab was too hidden for this... Few days ago, I was lucky enough to catch another of these guys changing skin, he was just on top of its old skin, I managed to get a shot, I'm quite happy with this opportunity!
I hope mine will have beautiful big anemones as yours soon... Do you feed him with something special, or is he just catching what you give to the other inhabitants of the tank?