Emerald crab and trumpet coral

[reef tank 2.0]

I recently got an emerald crab. Is say hes about the size of a dime. I took a look into the tank a few minutes ago, with lights off, to see if I could find him. I found him sitting on top of my trumpet coral. Could he be innocently eating food that he finds throughout, or is there anything on the trumpet that he'd find as a meal? First sign of him eating any corals, in the sump hes gonna go

 

[teddscau]

That emerald looks like he might be the predatory kind (ban ambush predator that eats fish). His colouration is dark, rather than green. There might be food (copepods, algae, etc.) in the coral that he's eating, he might just be perching there, but it's possible he might be trying to eat the torch's polyps. Wait, are his legs extremely fuzzy and full of sediment? If not, he's looking more and more like the predatory kind of emerald. To be safe, try putting him in your sump and offer him a herbivore meal (Nori) and a carnivore meal (silverside). My guys seem to be strictly herbivorous, even when I offer them frozen meaty foods. I know, people are gonna be shocked, but I feed my cleanup crew .

 

[mav.23]

What teddscau said. I have had emerald crabs for forever, and all of mine have been fine HOWEVER they have all been green with hairy legs. If he is the predatory kind he will be a little more work. I knew someone who had one of those a while ago and she said they were a big stress, but she was able to keep them. She would keep him very very well fed (offering food every couple of hours) but that isn't reasonable for some people. He is small now so I'd just keep an eye on him or try and catch him at night and see if he is eating it.

 

[reef tank 2.0]

Since posting this thread, I have seen him often. More times than not picking at the rocks/substrate. I have seen him on the stylophoras, and occasional trumpet like on day one. But come the next day when I look at every one of the corals that I KNOW he touched, every one of them has full bloom, and look 100% healthy. So I think he is just cleaning in the crevices. So for no I believe he is harmless. But will keep an eye on him. HE seems alright though. Sorry, SHE. I believe the females have claws that are the same size. Which she does.