are the red crabs safe to have in my tank?

ttmitsu

New member
I'm not sure what there called but i'm talking about the red ones that look like emerald crabs. they came on the rocls and i have about 7 of them and they are getting huge. i put 10 turbo snails in my tank the other day and there empty shells were all over the tank within a week. could they have done this or was it the hermit crabs?
 
Re: are the red crabs safe to have in my tank?

ttmitsu said:
I'm not sure what there called but i'm talking about the red ones that look like emerald crabs. they came on the rocls and i have about 7 of them and they are getting huge. i put 10 turbo snails in my tank the other day and there empty shells were all over the tank within a week. could they have done this or was it the hermit crabs?

Does he look like this?
45407crabgood1.jpg


I have a number of them in the tank and this one is by far the largest and getting bigger. I spied him today and he has obviosly grown some, he is at least 3 inches across! He is one heck of an algae eating machine, tearing through patches of algaea like they were nothing! I have caught him picking at my brain coral a time or two, mostly stealing food from it. So far I have not caught him doing anything really bad.
 
Hmm. Mine keep themselves alot cleaner than yours :P

red_crab.jpg


So far (10 months) I have not seen any negatives to these guys. They do occasionally pull food out of my sun corals but I just chase them off. I have never seen them messing with snails at all. I would guess that you have a gorilla crab or two, or a mantis in there eating them.
 
yeah the 2nd one looks like mine, except mine are huge now and more orange.
i caught 3 mantis when i first got the rock , i dont believe there are anymore of them. I was thinking there is probably a gorrilla crab, but from what i remember the small ones were impossible to catch. this is getting really annoying i cant keep buying snalls to have them all dead in a week. im thinking about getting rid of all the crabs and just having twice as many snails
 
Splach said:
Hmm. Mine keep themselves alot cleaner than yours :P

So far (10 months) I have not seen any negatives to these guys. They do occasionally pull food out of my sun corals but I just chase them off. I have never seen them messing with snails at all. I would guess that you have a gorilla crab or two, or a mantis in there eating them.

Most of mine look like yours, small, red/orange etc, but this one is huge and does decorate himself a bit!
 
I took a few crabs to my LFS. One was a decorator, one was a gorilla and the other I thought was a gorilla crab, but it didn't completely look like a gorilla crab. The guy at the LFS said that it was a red Emerald crab and to put it back in the tank because it's good. They had green ones there, which looked the same - only green. So, it's back in the tank and no damage is being done.

Your crabs may very well be red emerald crabs. I'm not sure what they would do to the snails, but the hermit crabs seem to be eating my snails.

-Brendan
 
I submitted my photos to the Ask Dr. Ron forum and he identified it as a decorator crab of some sort. The thread is here

They do look VERY similar to emerald Mithrax crabs and may be related for all I know.

I have a BUNCH in my tank. One extremely large one and a slew of smaller ones.
 
I did a search on Google for "libinia crab" and this is a page with images from the search. Some of the images, especially the bottom ones look very much like the crabs in question.
 
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My guess would be another mantis. Only my largest gorilla crab (2 1/2" inches) seemed to take down large snails. For the little gorillas I find that this is the best option:

Take a length of 1/4" stainless steel rod, if you are in school take it to the metal shop, if not use a vise and a hack saw to cut in in half 1" up. then rotate it 90 degrees and do it again. Then I carefully bent out the four prongs and sharpened them. Then I pointed them down. It gives me a four pointed trident arainged in a square. I put a piece of food up in the mouth of the trident and hover over their holes while I am feeding the tank. Spear and twist (the twisting is important, it is amazing how strong these things are).
 
on the TBS site. there is a very simple trap. cut a small water bottle in half. turn the cap end into the lower portion and now you have an inverted bottle half. place food inside. its a roach motel for crabs and mantis's. they check in but cant check out. safe and harmless.
 
great theory but i had 3 mantis shrimp and two of those traps and they never worked. i had to catch them by rediculios other methods
 
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