Emeral Crab Problem

[duddi]

So I got an emerald crab 3 days ago. I have seen him once since I have put him in. What I have seen is the remains of 2 hermits that he has killed (haven't seen him kill, but has to be him).

Does anyone have and emerald?
I know they are nocturnal, but do you ever see them during the day?
Do they kill everything they can get there pinchers on?
Do they ever eat algea? I got him to help keep things clean, but haven't seen him clean anything.

I guess my main question is why have one if you never see him and he kills other crabs and snails at night? Is there anything good that they do that outweighs the bad. If not he is going back to lfs.

 

[austinsdad]

How long you had the hermits? If they died from something else, the crab would definitely be seen eating on them. Seems to me that hermits can either get away or maybe defend themselves better than that.

You're not going to see the crab much IMO. Believe me, he is cleaning though. Leftover food, dead critters, etc. Even if he isn't the killer, you may just feel better with him not in your tank. He is supposed to be community tank/reef safe, but some say a crab is going to be a crab and do things other, supposedly more bad boy crabs will do.

 

[duddi]

Had the hermits for a week. I'm pretty sure the hermits were killed and didn't die on there own. I might just wait and see if more hermits start missing. I'm on vacation this weekend and I would hate to come back and see all my cleanup crew dead!!

 

[austinsdad]

I still believe they may have died on their own.

 

[duddi]

I only have my cleanup crew and the emerald. The hermits and snails seem to have plenty to eat on (algea, etc). Should I be dropping some food in for the crabs or just let them feed on the algea? I have put some mysis shrimp in before and they seemed to love it.

 

[austinsdad]

Oh yes. Drop some pellets in there maybe. Something that will make it to the bottom. If you haven't been feeding, maybe the hermits starved.

But no, algae won't keep them all feed.

What sized tank, how much rock, and how much of a cleaning crew is in there?

 

[duddi]

Its a 55 gallon with 40lbs live sand and 35lbs live rock. 20lbs of the rock was used to cycle and has a good bit of algea on it. The clean up crew has done a pretty good job of cleaning the rock.
I had 10 (8 now) blue legged hermits, a variety of 15 snails, and 1 emerald crab.

 

[roka64]

Do you have larger, empty shells for the hermits to move into, as they grow?

 

[duddi]

Yes, I do have larger shells. Like I said the hermits and snails have been in for a little over a week. I had seen no problem between the hermits and snails. And then I put the emerald in and the next day two hermits are dead!! I think he is going to have to go. Does he do anything good for the tank that the other cleanup crew does not.

 

[melosu58]

How do you know that they did not move to another shell. As AD said there are many variables

 

[lando]

I would be too quick to blam the emerald either. Inverts are sensitive to poor or changing water parameters. Can you post your SG, NH3, NO2, NO3, Ph and temp?

 

[duddi]

I know they were killed because I saw the blue legs laying on the sand bed. I guess he doesn't like the taste of those. I'm not going to get rid of him yet.
My parameters are good.
ammonia 0
nitrite 0
ph 8.2-4
sg 1.22
temp 76
nitrate 10
My tank is only 7 weeks old. I filled the tank with tap water to find out that my water was high in nitrate and no telling what else. So I bought a ro/di filter. I did a 75% change after cycle and another 20% change before adding the crew. Still trying to get the nitrates to 0.

 

[austinsdad]

I saw the blue legs laying on the sand bed

You did see an empty shell, right? If not maybe the crab just molted.

Still, you won't be OK until you return the crab I'll bet.

 

[duddi]

The problem is that I have around 10 empty shells in my tank. Not sure I know what molting is?

 

[lando]

Inverts like shrimp and crabs molt. Think of it as snake shedding its skin. It is how they grow. The molts look exactly like the crab and are often mistaken for a dead animal.

 

[roka64]

If not maybe the crab just molted.

This is what I was thinking. Mine took about 3 days to move. I thought mine was dead, but I sawhim moving 3 days after his molt.

 

[drummerj]

hmmm. i just got my emerald crab today with my cleanup crew. I was told they are friendly and wont bug anything. I've also a question. i have a blue clawed lobster, does anyone think that the crab and lobster will clash?

 

[melosu58]

I have a lobster,crab,shrimp and dozens of hermits. No problems that I`ve ever seen. My Lobster is purple and orange. I forget the name.