Can hermit crabs/emerald crabs eat corals?

[gnatp2]

I've had some issues recently with my birdsnest losing polyps. At first I thought it was an issue of poor water quality (which still might be the case), but tonight I noticed that my large emerald crab was in the branches of the coral. I tried to see if he was picking at the polyps, but he ran away when I shined the light on him. He left and then came right back about 20 mins later. Made me a bit suspicious. Also, on my montipora digitata, a couple small blue leg hermit crabs were on parts of the coral where chunks of tissue and polyps are missing.

I've always heard that these guys were reef safe, but could they be eating my corals? I moved from frozen food cubes to flake food about 2 months ago and am wondering if these guys are just not getting enough to eat.

Nate

 

[NYreefNoob]

corals

i really doubt it on either, the emerald may have damaged it from trying to pick something out of it. and the hermits with walk and climb all over them and maybe irritate corals. but dder things have happened so you never know

 

[loismustdie]

I've lost corals to emerald crabs. Yet strangely, having them in my tank never had any effect on bubble algae. I think it's another GARF myth.

 

[tripstank]

That sounds odd to me, I have never witnessed nor lost any corals to either.

 

[e.muehlbauer]

I have been warned (by LFS workers) that emerald crabs are not reef safe. However, I have never found them to damage corals. I have had one or 2 that ate Valonia, but most of them ignore it. As for hermits, I have never seen hermits attack coral, although they walk all over it. My guess is that something else happened, and the hermits were eating dead or damaged tissue. Take care, Eric

 

[Chiefmcfuz]

Most crabs you see picking at corals are picking at either food, algae, etc on the coral. Crabs are opportunistic animals and will also not hesitate to clean up sick or dying animals. They may pick at a sick piece of coral out of instinct.

 

[ellebelle]

I had emerald crabs (that DID eat my bubble algae), but they also tended to pick on other macroalgae in my tank. I once saw one of them destroy a patch of zoanthids trying to get to a piece of macroalgae growing between them.

 

[Dmitry]

I had an Emerald take a bite out of my Clown once upon a time. He was banished to the sump. I don't trust the little buggers!

 

[bigbris1]

I had mysterious chunks missing out of my green payls & thought it to be either my hippo tang or potters angel. Then when the emerald crab died, guess what? No more missing chunks. Problem solved.

 

[noodleman]

i had emerald crabs eat my stylopora while i was watching

 

[gnatp2]

Ok, well that's that. Free emerald crab.

 

[jgiordano]

Ok, well that's that. Free emerald crab.

If you are able to grab him turn him over and see if he is a male. Males seem to be (IMLE) more aggressive towards fish and corals, while the females seem to be awesome @ algae. Sometimes males have HUGE claws too, when compared to the rest of their body.

 

[LeslieS]

Thanks Nate,

He has been added to the tank. I'll keep you guys updated regarding his eating habits.