Crabs that look like ?

Doug · #1 02-21-2009, 01:34 PM

Good title. I bought a couple pieces of new rock for my tank. Have them in a bucket of saltwater. They have been in a holding tank for a few months now.

So I treated the rock with exit the other day and was looking it over last night. And there was a crab sitting there looking at me. Identical to a emerald. Scurried back into its hole before I could do anything about it. Left the rock out of the water for a few hrs. to see if it would come back out but that was futile.

I,m searching as we speak but wondered if any similar to emeralds exist that should not be in out tanks?
Thanks

High tide · #2 02-21-2009, 03:33 PM

I think it's pretty safe to say, if it looks like an emerald and you know it's not, the crab is going to be trouble. With crabs it's not worth the gamble because so few are actually reef safe. As much as I hate killing a helpless organism, how much is that crab going to kill if you leave it?

Jason McK · #3 02-21-2009, 03:47 PM

I've had a Black or dark dark purple Mathrix crab. Same flate cupped claws as an emerald crab. It was fine in my tank for about 1 year then it got big enough to start eating SPS. It would break off a branch and eat the entire branch

J

Snaz · #4 02-21-2009, 04:14 PM

Any crab is an opportunistic feeder and should be regarded as suspect until proven otherwise. If it is a Mithrax and has the blunted claws as Jason describes then treat as you would any Emerald(Mithrax) crab.

That said I have two smaller red eyed, pointy black clawed crabs(Xanthid) that I'm sure does some damage but I leave in my tank as part of the CUC and I think they look neat.

Crabs are a personal thing.

High tide · #5 02-21-2009, 07:28 PM

Quote:

Originally Posted by Snaz

Any crab is an opportunistic feeder and should be regarded as suspect until proven otherwise. If it is a Mithrax and has the blunted claws as Jason describes then treat as you would any Emerald(Mithrax) crab.

That said I have two smaller red eyed, pointy black clawed crabs(Xanthid) that I'm sure does some damage but I leave in my tank as part of the CUC and I think they look neat.

Crabs are a personal thing.

Just because it has blunted flat tips on it's claws doesn't mean it's a relatively peaceful herbivore/scavenger like an emerald. Many Mithrax get large and predatory, like the one in Jason's tank. Be cautious!!

Doug · #6 02-21-2009, 07:29 PM

Quote:

Originally Posted by High tide

I think it's pretty safe to say, if it looks like an emerald and you know it's not, the crab is going to be trouble. With crabs it's not worth the gamble because so few are actually reef safe. As much as I hate killing a helpless organism, how much is that crab going to kill if you leave it?

It does look like and I,m guessing thats what it is, unless its one like Jason mentioned.

Doug · #7 02-21-2009, 07:33 PM

Thanks Jason & Snaz. Those are good possibilities. Biggest problem was when I touched it, {should have poked it good}, back into the rock it went. Guess enough water is trapped in the rock for them to survive also.

Have not seen it since.

christyf5 · #8 02-22-2009, 03:22 AM

Fondue forks work really well

Doug · #9 02-22-2009, 02:08 PM

Well the "sob", has gone into hiding or croaked when I had it out of the water, {yea right}, or somehow managed to get to another rock.

Christy, I now wish I had had one handy when I poked him the first time.

So, stay tuned for the follow up story of the coral munching crab that an aquarist could have gotten rid of before going into a tank but never.