Emerald Crab

[Lance_Celli]

Hi All,

On 2 seperate occasions in the past, I've purchased an emerald crab because I was informed that they tend to eat bubble algea (which I have quite a bit of in my tank). In both instances the emerald crab would start to lose his coloring after being in my tank for about a month. It would fade from bright green to a dull green to really pale an eventually die. I'm guessing this is due to some sort of nutrient defficiency, but i'm not sure what that might be. Has anybody ever encountered this before and found a way to rememdy it? What do people feed these crabs?

Setup:
Tank is 55 Gallon, 2 110 Watt VHO (1 50/50 and 1 actintic). Live rock and protein skimmer in the sump for filtration. I have 1 Yellow Tang, 1 Percula clown and a cardinal. I've got a seabae anemone i've had for almost 5 years now (how long do they live?), some finger leather corals (1 reproduced into 3), a purple mushroom which reproduced from 1 to probably 60 or 70 mushrooms (it spreads like a weed), 2 metallic green mushrooms, some green star polyps, some other green polyps which weren't named when I got them (got it from free off the bottom of a tank at the LFS) and a stylophora coral.

I add calcium via a kalkwasser drip, strontium and iodine once per week and occasionally feed some phytoplankton. Othen then that I just do pwc's every 2-3 weeks.

Thanks,
-L

 

[Hara]

Emerald crabs eat many things besides the valonia. I rather doubt it is a nutrient deficiency as it was probably scavenging pretty well whenever you fed. I am wondering if you are testing for iodine and strontium levels as well as alkalinity, ph and calcium. The things you are adding most likely are not needed. Water changes replenish those items and if you are not testing, you might have things out of whack. Inverts are highly intolerant of chemical imbalances.

That is just some food for thought.

 

[GinaD]

That is just some food for thought.

 

[ColdFish]

My emerald crabs do pretty well with little to no extra attention. The one that has been in my FOWLR the longest hitched in on the first liverock that I placed in the tank. I was worried at first that he might not survive since the tank had not been running very long. I would go for very long stretches, I mean like up to a month, where I wouldn't see him at all. Eventually I would spot him in the tank. I've sinced added a couple more, and it's the same deal. If I get the flashlight out after the lights go down for the night I can usually spot them.

Mine also do the color change thing, and I was assuming it's because they molt? Have not had a chance to check into it but I'm guessing that they do. Are you sure that what you're seeing as a dead crab isn't old cast-off shell?

The only special attention that mine get at all is some nori attached to a small piece of LR rubble that I'll place in the tank maybe like every couple of weeks for whoever want to eat it. I don't really have herbivorous fish, but I do the nori thing mainly for the benefit of my clean-up crew. My flame angel hates nori, and that was what I originally bought the stuff for. A small piece every once in a while does get eaten up though, but it happens after lights out.