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emerald crab question :?:

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deadrose

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Joined
Jul 1, 2003
Messages
96
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Vashon
How can you tell a molt from a dead crab? Is there a large obvious opening on the shell? If so, where?

I've been hugely busy the past few days with an annual catering job of mine, so haven't been keeping the usual eagle eye on my tank. Today I found what appeared to be my emerald... but when I fished it out and held it to the light it appeared empty. I haven't found a hole yet. The color is quite faded for the most part.

So, what are the odds that he's molted vs. died? He'd been eating like a pig... :). My other crabs and snails are fine.

Heidi
 

esmith

AQUAMANIAC
Joined
Oct 9, 2003
Messages
451
Location
Shoreline, WA
Emerald Crab

I would say that he more than likely just molted. I had this same thing happen to me, I couldn't find any holes of where he could have gotten out but when I investigated further I realized that they shell was in fact empty. Try breaking it open to look and see.

Mine just molted again some time between yesterday and this morning and this time the entire top of the shell had been pealed open from the back towards his head(just like peeling the top off a crab you eat), and the shell was sitting halfway in my anenome so I thought thought the anenome had eaten him but I found him sitting under a rock so all is good.

I am not completely sure wether they always molt in this same fashion because this is only the second time he's molted.

Hope this helps.

Eliyah
 

mattseattle

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Joined
Jul 15, 2003
Messages
2,694
Location
Seattle, WA
my sally lightfoot crab did this a few weeks ago. i was looking around the live rock and i saw 'her' in the back. well she wasn't moving and looked dead. i reached in and touched her and she still didn't move so i took out the shell then i remember reading about someone else having a crab that molted and had thought it had died. i looked closer and realized the eyes weren't really there so i broke open the shell and sure enough it was a molt. no innards or what i thought should be in there. it was just the exoskeleton. i started looking around with a flashlight in the rocks and there she was hanging upside down in one of the caves. it's pretty wild.

the other day i found a hermit crab molt....little easier to tell it's a molt than the crab. my cleaner shrimp also molts about every 3 weeks and it's easier to distinguish as well. the crab molt was definitely difficult. after the molt though she was much much more vibrant than before. i did look closely at the shell and there was a tiny opening in the back. i can't imagine how you can slide your whole body through a tiny little crack but somehow they do. must be pretty stressful on them to do this.
 

Alice

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Joined
Jul 18, 2003
Messages
1,108
Emerald crabs complete their molt by pushing their way out of a slit on the underside; sally lightfoots through the slit in the back. The Sally molt really fooled me the first time I found one.

Crabs and shrimp hide while they're molting as they are vulnerable to predation then. If you see one of them out while they are molting chances are the molt is not going well and they will die. I've tried to help along a couple of shrimp I found like this to no avail. :(

If you have a fire/blood shrimp you'll be able to tell when it's close to the time for them to molt, they will get very dark in color. After the molt they will be the nice brilliant red again.

Alice
 

Minh Nguyen

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Joined
Oct 3, 2003
Messages
95
mattseattle said:
...... the crab molt was definitely difficult. after the molt though she was much much more vibrant than before. i did look closely at the shell and there was a tiny opening in the back. i can't imagine how you can slide your whole body through a tiny little crack but somehow they do. must be pretty stressful on them to do this.
Crabs do not go out through the "tiny little crack". Rather, their top popped open like a car hood. It separated where the legs join the body on the under side of the crab.
What crustaceans, once they are ready to molt, do is to take in water and swell up their body, because the increase in volume, the shell popped open along the weakest lines. The animal shed the shell, then their new shell harden over a few hours. They are very vulnerable when the change shell because they cannot move fast and have essentially no armor.
If there is defect in the shell where it does not popped where it should, the animal died during molt.
Minh
 

deadrose

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Joined
Jul 1, 2003
Messages
96
Location
Vashon
I never did find a hole in the shell, but last night as I was putting the tank to bed I saw a considerably larger emerald crab lurking around the back of the rockwork :)

Everyone seems to be doing well, including the peppermint shrimp I added Saturday night (after spotting 2 small aiptasia)

Ive been seeing a lot of larger 'bugs' running around in there, some 1/8" or larger. My best description would be tiny shrimp. Amphipods? (They don't look like pillbugs).

Every time my sister comes over now she walks immediately to the tank and stands there watching it for 10-15 minutes before she does *anything* else. I think I have another one hooked :D

Heidi
 
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