Crabs attacking polyps?

[r10701]

I have a 29 bio cube. Recently a bot 2 poly frags and placed them in the tank. Each moring one of them would be on the sand upside down. Finally one day it completely disappeared. I tore the tank apart looking for it. Nothing. The second larger brown polyps were doing well but now they are getting knocked or pulled off their rock. I witnessed a hermit crab pull it down yesterday. Today I saw a hermit by the polyps messing around this morning? Do snails or crabs eat polyps?

[Rosseau]

I don't think that hermit's will be eating your polyp's. They may knock them over and move them around. Then they can drift around to some long lost corner of your tank...


Some hitchhikers may also eat zoanthids... but I don't know what ones.

[wingmans10]

I have had my hermits eat "bad polyps" that didnt look like they were doing well to start with on new additions. But they have left all the healthy polyps alone on the same frag.

[kathainbowen]

Small hermits are not an issue, for the most part. Most hermits get considered "not reef safe" for their large size and dragging of shells across corals- doing damage and destroying them- leading to the previously mentioned consumption of bad polyps. But, in that case, we're talking about things like the red hairy hermit, crabs that easily end up being somewhere between golfball to baseball sized.

However, Mithrix crabs (Emerald Crabs) have been known to, on the occasion, just rip off polyps, just as zoanthids, star polyps, small mushrooms, xenia, etc. On the downside, in smaller colonies, and frags, this can be quite annoying. In larger colonies- it can be like having your own little "frag crew." They had a sort of 50/50 reputation. Some people love 'em and have never had an issue. Some people hate 'em and only see theirs when they come out to rip up a new mess.

G'luck!

[brushman]

Just got some polyp frags and I think my emeralds are munching a little......may have to get rid of them. I would much rather have my coral than the crabs!

[smithcreek]

My emerald's have never touched anything that wasn't on it's way out already. They're really good at weeding out the bad polyps. I have a pretty big clean-up crew and have virtually no algea, so a couple times when I put a new plug in the tank an emeralds has rip the mat with several polyps off the plug to get at algea underneath, but not touch the polyps.

[pv1191]

My hernits and emeralds have not damaged any corals so far. But, they do make quite a mess. One of my emerlds took out my first percula so I filled his favorite hiding spot with LR rubble. within days the rubble was moved out and spread out all over my sand bed. I keep putting it back in but within a day or two my tank looks like a marine tweeker pad. All I need to do is put a couple of hotwheels up on blocks and look would be complete.

[NanoKat]

I had to get rid of an emerald because he seemed to get a taste for my softies...he was munching on my shrooms. I've heard that the males are also worse than the females in the emeralds. I have had my hermits knock things over, but never seen them eat anything they shouldn't. I recently lost my favorite, my white claw hermit...he was awesome!

[kathainbowen]

I actuallly had a client bring back one of the rumored "bad Emeralds" after swearing up and down that they wouldn't tear up polyps, trying to reassuring my client that mithrix crabs only picked at damaged or dying polyps. I put him in a tank with some rather bland zoas. After an hour of him behaving like a perfectly normal crab, I was pretty shocked to see the little bugger ripping off polyps for no reason.

.... although, it was pretty cute to watch this little crab look like he was tossing the polyps over his shoulder.

Like I said, most people don't end up getting "problem" emerald crabs. For the most part, I have enjoyed keeping them and watching their weird little antics. But, then again, I have a soft spot for crustaceans. XD