green emerald crab

[james5593]

My green emerald crab is getting what looks like hair algae all over it. The weird thing is that there is no hair algae anywhere in my tank. Is this hair algae or possibly something else?

[seahorsejl]

All over it, or just on it's legs? Mine has hair on it's legs only that could look like hair algae (see picture).

[james5593]

All over it, or just on it's legs? Mine has hair on it's legs only that could look like hair algae (see picture).

On his legs and his back.

[Mini_GBR]

can i ask, how do you two like your emeralds, i've heard mixed reviews, but I have a really bad hair algae problem and can see the start of some bubble algae. Has he picked on anything, or is it a mild manned resident that does its duty.

[seahorsejl]

On his legs and his back.

 

That sounds normal then.

 

 

can i ask, how do you two like your emeralds, i've heard mixed reviews, but I have a really bad hair algae problem and can see the start of some bubble algae. Has he picked on anything, or is it a mild manned resident that does its duty.

 

Well, not too much in my tank to pick on yet. He was added to help control the bubble algae I have in the tank. But the problem is, I think he is finding other types of algae to munch on instead

 

Also, most of the bubble algae is starting to get pretty big, so I am going to have to manually remove them.

 

But all in all, I haven't had any problem with him.

[andykee]

i love my emerald. he is great to watch and has never bothered anything in my tank. never see any bubble algae, but mine won't eat hair algae, so i wouldn't count on him eating much of that.

[kinetic]

KILL THEM!

 

mine killed my gobies, and destroyed almost $200 worth of corals.

 

SURE it ate all the bubble algae... but hell, bubble algae would be better then losing 2 gobies and some corals.

 

and yes, i kept him well fed with algae wafers every day.

[wwildcats04]

mine is an oustanding resident. Just try and get a female crab if @ all possible (they dont have the large pinchers) and you wont really notice problems with aggresion and such. Mine ate one of my bubbles but not the other two, I am going to purchase another one asap though.

[jenn_jeffery]

I love mine! I have a few in my 55 gal. and a couple in the 12 nano. They eat all algaes, and haven't messed with anything they're not supposed to.

[Mini_GBR]

is there really evidence that a female one is less likely to pick on zoas and other things than a male would. That is interesting.

[jimmy595]

I love my emerald crab, he got me back into the hobby by cleaning up all the hair algae in my overgrown marine tank in like a month he had it all cleaned up. Mine is very mild mannered, it has been blamed for knocking some rocks over now and then, Mine also has one bum claw, the bottom pincher's tip is broken off, so maybe that makes it a more friendly crab.

[james5593]

my emerald did kill my mandarin but does not bother my corals too much. He is extremely strong though and moves things that are in his way like my L.R and sometimes corals.

[Undertheradar]

Male emeralds (larger claws) can be a PITA after just a molt or two. Their claws can easily catch fish and rip snails out of shells. I had one that would eat red flatworms, and even grape macro algae (like it was a bunch of grapes...whole bunch at a time like a wood chipper). The females with smaller claws are model citizens in my book...but the large claw males can get nasty. I saw one at the LFS last week that must have been the largest male I have ever seen...almost 3" across and dark green. He decided to kill and eat another emerald while I was there...mean bugger.

[BytheSea]

can i ask, how do you two like your emeralds, i've heard mixed reviews, but I have a really bad hair algae problem and can see the start of some bubble algae. Has he picked on anything, or is it a mild manned resident that does its duty.

 

For 8 months now mine has been mild manner. He does not bother any corals but will occasionally grab at a fish. Their great algae eaters, no more bubble algae.

[kinetic]

wow, didn't know about the females. I definately have a gigantic male. His pinchers are really ridiculously large. He's also at least 2" across his body now.

 

he does eat all my algae up, it's amazing, but he's also killed so much stuff. most definately not a good trade off. Anyway to tell if a small younger emerald is a female or not? Are pinchers that distinguishable at a younger age?

[Arklier]

All true crabs are sexed using the same method. You look on the animal's underside at the plate between the pairs of legs. It has two parts, and on the female the posterior plate is very large, much larger and wider than the antirior plate. On the males, the posterior plate is long and narrow, almost arrowhead shaped. You can see the differences in this picture of dungeness crabs, but it's the same for all true crabs:

 

 

Female on the top, male on the bottom.

[herb]

thanks that is good to know

 

 

herb

All true crabs are sexed using the same method. You look on the animal's underside at the plate between the pairs of legs. It has two parts, and on the female the posterior plate is very large, much larger and wider than the antirior plate. On the males, the posterior plate is long and narrow, almost arrowhead shaped. You can see the differences in this picture of dungeness crabs, but it's the same for all true crabs:

 

 

Female on the top, male on the bottom.

[Copper1bandfly]

i hated mine my stepdad has a 75 reef and i have a 30g FOWLR and we each got one b/c we both LIKED them..i had a blue damsel which he killed and a firefish who did live but he chopped off his top fin..they are vicious to anything that sleeps on the bottom or any bottom dwelling fish like blennys, gobys, etc.

 

i then took mine and dropped him into the reef where he hasnt bothered anyone but we have no bottom dwellers in there..we are thinking of possibly putting in a manderin which IMO will probably get killed now there is 2 of them one which is HUGE

[zash]

Mine have descimated the hair algae in my tank. The biggest problem I have is them knocking things over. I've got a couple of small red mushrooms on a piece of rubble that gets knocked over every couple of days.

[Fanof49ASU]

Any guess as to which sex this is? It doesn't really resemble the crabs above.

 

[utes2k5]

Any guess as to which sex this is? It doesn't really resemble the crabs above.

 

 

 

Looks like a fem to me (According to the above picture)

[kinetic]

it's porportion of the claws are tiny compared to mine, this has got to be a female ^

[NanoBound]

I have to agree with some of you about the emerald being a big pain in the butt!!! In the last few days mine ate 2 big zoo frags and a snail . I wonder what is on his menu tonight!!! I have tried to catch him.....but that is almost impossiable. He stays close on the rocks and retreats to impossiable places to retreive him from. And I am not about to brake down my live rock. Guess I will have to find something that loves to eat emeralds and is completely reef safe.( Is there such a thing?).

[Callous1]

Any guess as to which sex this is? It doesn't really resemble the crabs above.

 

 

I'd agree yours is definitly a female, here's a picture of mine making it easier to compare with the picture Arklier provided

 

[james5593]

I have to agree with some of you about the emerald being a big pain in the butt!!! In the last few days mine ate 2 big zoo frags and a snail . I wonder what is on his menu tonight!!! I have tried to catch him.....but that is almost impossiable. He stays close on the rocks and retreats to impossiable places to retreive him from. And I am not about to brake down my live rock. Guess I will have to find something that loves to eat emeralds and is completely reef safe.( Is there such a thing?).

I catch mine every time I put my hand in the tank. He attacks my hand and latches on. He thinks he is a pit bull. So when I decide to catch him and remove him I might have a couple friends over and take bets on how long it will take for him to bite my finger.