Stunned Crabs after Acclimation

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sevise

Aquarium Advice Activist
Joined
Jul 28, 2004
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184
Location
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My tank(120Gal + 30Gal fuge) finished cycling. Am 0, Nitrite 0, Nitrate 10. I only did a 20Gal water change because the Nitrates were low to begin with. I pickd up 4 Emerald crabs at the LFS to clean all the dead fuzz off the rocks and to start knocking down the algae. They were quite active at the LFS, it took the salesperson almost 10 minutes to bag 4 of them because they kept running and pinching. I did a 3 hour drip acclimation during which there activity level dropped. After placing them in the main they curled up and didn't move. After about an hour I picked each one up and moved it onto the LR. They latched on but haven't moved since, its been about 2 hours. Tank lights have been off the entire time, the room has been dimly lit.

Are they just in shock from the transfer?
Did I acclimate them wrong?
 
Give them a day, most animals seem to react negatively (at first) to a transfer. As long as the temp, salinity and PH match closely when you let them loose, you did everything right.
 
I have only one experience, but after a little over an hour of acclimation, I set an emerald on a hairy rock and he started shoving algae in his mouth as fast as he could right away. When he was still, his little mouth parts were always waving energetically--I'd watch for that.
 
When I got home fro work they all had moved. 1 is MIA, but theres alot of room for him to hide. The ones I can see mouth parts are always moving, 1 ate a few bites of stuff but is now upside down on the rock. Hopefully there just a little stunned from the transfer. I've decided to wait for a while to get the rest of the crew, just in case something is wrong in the tank.

Maybe if I put the Mantis back in they'll run and hide...
 
While I was feeding my Mantis some shrimp I wondered if the emeralds would react to some shrimp. The emeralds sprung into action when the shrimp got within an inch of them. They grabbed it add sucked it right down, definately a good sign. About 8 hours later I get home and 2 of them are on there backs in the sand again, there mouth parts still moving.

The pattern seems to be they roll around on the sandbed until they hit soem rock. They'll stay on the rock for a while taking in clumps of stuff. Then fall of the rock curl into a ball and roll around some more.

Are they overfeeding perhaps and just eating til they drop?

When one of the crabs was on its back I noticed a weird structure on its carapice. On the underside coming from the end was a small tail, you could see a matching grove in the carapice. Anyone know what this is?
 
sevise said:
The pattern seems to be they roll around on the sandbed until they hit soem rock. They'll stay on the rock for a while taking in clumps of stuff. Then fall of the rock curl into a ball and roll around some more.

When one of the crabs was on its back I noticed a weird structure on its carapice. On the underside coming from the end was a small tail, you could see a matching grove in the carapice. Anyone know what this is?
Are you sure these are Emerald Crabs? This is some strange behavior for them. Got a pic?
 
The pictures aren't best, and none show a good view of the carapice.
emerald1.JPG

emerald3.JPG

Obviously they are green, the tops of the carapice are rough, The legs are hairy, front claws vary from green to almost black, tips of the claws are white.

They will go active for about a minute and pile food into their mouths. Then they stay still for a while. Is this normal? My experience watching them at the LFS was they piled food into there mouths non-stop? I'm planning to take a water sample to my LFS to double check the chemistry. Am I just worrying too much about them since they're my first additions?
 
They definitely look like emerald crabs. That is some strange behavior though. Mine were shy and only came out in full view at night. The rolling along the sand bed doesn't sound right at all. That tail thing I believe is called an apron. I know blue crabs can be sexed by the shape of it. I would assume the same could be done for emeralds. Thin would be male, wide would be female.
HTH
 
Well, emerald crabs that I have seen do not have black claws with white tips. Are the claws cup shaped? Or are they shaped like scissors? Hard to tell from the pick.
Ya, the rolling around threw me off to.
 
2 of the crabs have lighter claws while 2 have very dark green ones. The very tips are white and flat pads. They haven't rolled around on the sand yet today but they still seem pretty lethargic. Thanks for all the help.
 
Mine had the dark claws with white tips, too. Reading about emeralds, I learned that there are several different species sold under the generic "emerald" name--some of the variations we're talking about might be due to that?
 
All but one of the crabs is now missing, its a big tank and since it sits in the corner I only have 2 views. The one I can see still moves and eats from time to time. I took a sample of water to the LFS the other day, Ammonia 0, Nitrite 0, Nitrate 20. I read inverts normally molt when added to a tank, is it possible this is whats going on? Do inverts normally slow down and find somewhere to hide in anticipation for a molt or is more spur of the moment?
 
Emerald crabs tend to hide during the day and forage at night. If you have a decent amount of rock, they have plenty of places to do this.
 
Could this be a symptom that the temp is too high. I've been running the tank at around 80-81. Well going over things I noticed liveaquaria.com has Emaralds listed as preferring water 76-78.

I've started to lower the temp, I'm shooting for 78-80 and see if that makes a difference.
 
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