Emerald Crab coral muncher

[Anonymous]

I've had an emerald crab for about a month now. I've seen it feeling around my elegance coral, but he doesn't seem to be doing any harm.

I haven't seen him eating any bubble algea yet. Hopefully he'll eat it eventutally.

 

[Anonymous]

Last night I observed my emerald pulling polyps off the branches of my pink birds nest. He's banished until I figure out what to do with him.

 

[Mouse]

I have just bought a new emerald crab for my reef in an attempt to controll bubble algie. Its not that the algie is a real problem but the crab was there and he was so disgustingly ugly i had to have it. Put the crab in my tank and it seemed fine for a while, after about half an hour it walked onto my beutiful metallic green flowerpot coral, and took a huge bite out of the top of it. There is now a massive hole going through to the skeleton below. Im hoping that the little guy was just curious having never seen one before but has anyone else had this problem. If there troublesome ill have to launch it. Lucky there slower than molassas.

 

[Mouse]

Thanks guys, anymore trouble from this little critter and he's launched.

 

[EnchantedSea]

Mouse, I've had an Emerald Green Crab for about six months now and he hasn't touched any of my corals. All he eats is algae. Someone told me to be sure that they are true Emeralds by checking the inside of their elbow for a red dot. If they don't have one, its not an Emerald.

 

[2poor2reef]

I asked my crab and he admitted to being a true emerald. Yet he is in the sump due to polyp nippery. He admits to many things now that he is incarcerated. Anyone who has kept these guys long enough knows that they nip corals. I've had them for four years and as they get bigger their dietary repetoire expands. I still move mine to my polyp tank to clean up valonia once in a while. He can nip all the buttons he wants. I keep him fed with grape calupera in the sump and when he sees a valonia he thinks of it like home cookin'.

 

[Mouse]

Ahh, i think it is time i had a chat with my little freind, i could be harbouring an imposter. Allthough i think its probably just that he's an unruly little skamp that needs to bear witness to my rod of correction.Oh yes he will learn the ways of the force.

 

[Jacob1]

"Polyp Nippery"
Sounds like a theme to an monty python sketch.

Sorry, I just love english humor.

 

[danmhippo]

I removed all 3 of my emerald crabs the last time I have to re-arrange the whole tank due to a mishap. Back to the LFS them goes. Mine have developed amazing appetites for anything that they can get a nip on. Algae (micro and macro), coralline, polyps, clam meats, and bristtle worms (if they can get their claws on). I admit that when they were small, their diet were pretty much limited to just algae and greeneries. However, when mine grow older, its pretty much anything they can grab a hold on. I still have a sponge that is missing a corner.

I failed to have a nice chat with them when I removed them to check if they got spots. I guess that doesn't matter now.

 

[reefturkey]

they are pretty bad whn they get big. I caught mine easting my xenia and colt coral. They are very unpridictable and can go crazy. I wouldn't recommend them.

 

[MIKE NY1]

A couple of months ago I caught my Emerald eating the polyps of my Xenia so I started
feeding it Seaweed Selects a couple of times week and so far it's behaving itself.

Mike

 

[Mouse]

Mike, love the suggestion. Bribery must be he way to go. And once ive coaxed him out of his little hole, im going to take him out and bite its legs off. Alternatively i can give it back to the LFS and boycott the little bas*ards from being sold again. I recently introduced my LFS to sally lightfots, i was a little nervous about introducing these guys to my reef, but compared to the emerald clawed menace there absolute angels. I dont understand all the hype surrounding these crabs when all they do is cause damage, not to mention they look about as attractive as a bull dog chewing a wasp. What have GARF let all these people in for? Thanks for the info guys, i think that yet again the books are wrong, these critters are defenatley no freind of mine.

 

[hectina]

I have one and he eats my coraline algae. He doesn't eat too much of it. Although I have read from different posts that this may actually be beneficial. He he does any damage to my polyps, I will relocate him to a trigger tank at my LFS.

I have a coraline eating emerald crab, a blood shrimp that killed a cleaner shrimp, and a bicolor blenny that beats up damsels (a good thing actually). Boy were theses books helpful

 

[2poor2reef]

Emerald crabs have their place in our hobby. There are few better critters at eating hair algae which makes them very useful in new tanks where algae outbreaks are inevitable and you haven't stocked corals yet. They eat valonia which few other animals do although even they don't seem to prefer it when better is around. Mine regularly spends time in a low-light polyp tank among buttons and parazoanthus and mushrooms and gsp where the loss of a few is a blessing.

These guys were introduced into the hobby about four years ago (commonly available anyway) becuase we needed something that would eat valonia which can become a plague if uncontrolled. Also, for a mithrax crab they are pretty sedate. It's just that people were initially told that they were completely reef safe, which it turns out they aren't. I would not keep them in an sps tank, but they have their uses. And I think they're cool looking and have great little personalities. They are the only critter in my tank that will sword fight me over a piece of shrimp.

 

[kjoz]

Is there some other reef safe critter that will eat Valonia?

 

[danmhippo]

I do have some, 10 actually. I believe you probably have some too.......your fingeralia!

Besides that, try a Indian Ocean Sail-Fin Tang. Make sure your tank qualifies to keep a handsome fish like that.

 

[kjoz]

(valonia).But aren't they hard to get off rock without breaking them? The ones I have are tiny and in a cluster. I don't think I could get ahold on them. If I pull the rock out and pull them off with needle nose pliers, will the rock be safe to put back in the tank?

 

[SPC]

Kjoz, sure, the rock wont be out of the water long enough to hurt anything.
Steve

 

[blinky]

I have 3 emerald crabs, I've seen them hide in acroporas at night, but never known then to do any harm. However, I do have _Marine Invertebrates and plants of the living reef_, by Patrick Colin, It says "It occurs among the branches of porites furcata and feeds on the expanded polyps at night". Also "crabs have been seen to devour 10 polyps in a minute." I was told by Morgan at Inland Aquatics that if there is no algae for them to eat, they will attack snails, other crabs, and yes, corals also. He also said they prefer macro algae.

Brian

 

[kjoz]

Thank you Steve.