Hannibal Cannibalizing Emerald Crab

[zoso]

Hey ,
In my Biocube 16 I have peaceful content looking Emerald Crab . He has been enjoying the last few fish I have added as a tasty evening snack. He has killed a total of 4 fish , the last being a small rather peaceful 6 stripe wrasse that was doing a great job of cleaning up a flatworm problem .
I thought the first few deaths were due to my error , but everything was dead on as the perimeters of my tank were great . The tank is 7 months old , well seeded and looks great.
Yesterday morning I found the crab feasting on the 6 stripe wrasse. I believe he captured and killed it while it lay sleeping in its mucus membrane and was defenceless for the mere moment it may of taken for the crab to grab the wrasse.
My question is how I can lure the crab out or into a trap to capture him ? Being a Biocube 16 with a lot of hiding spots in the rock it is going to be a dismantling and damaging potential to many corals that have spread out on the rocks and I’d rather not do that.
The odd thing also is I have a fire goby that is the first fish I bought for this tank and he is a trooper ! I’m not sure how he has survived the crab but I’m sure he is traumatized from watching this psychotic crab at work on his tank mates.
I do not want to harm the crab as he is just doing what he was designed to do . I’d like to get him out soon as I hope to get another wrasse this weekend at the Niagra Falls Coral Show.
Any advise would be greatly appreciated.
Cheers

 

[S-t-r-e-t-c-h]

More likely the crab was scavenging the fish that passed. They're not really well equipped to catch a healthy fish, sleeping or not. If anything, they're more likely to consume sessile inverts, like corals...

In terms of catching the crab, maybe try putting a fish net in the tank at night with a piece of krill or a clam on the half shell. When he goes to get it, pull out the net...

 

[Biocube32]

Picture of crab?

 

[zoso]

no picture and really not required , but thanks

 

[Jvesche20]

Heres my thoughts on how to catch him. Find where he is and take that rock out that he's on.

Take out all the rocks if you can't find him.

build a trap with a water bottle, maybe put some nori or other stuff inside and make it so once he enters and he can't leave.

Best of luck catching a crab!

 

[Shredder99]

Dang! How big is this Emerald Crab? I have two in my 32G Biocube and I rarely see them and I have not lost a fish to them. Mine are tiny; about 1.5 inches. Makes me wonder how long term they will be.

As far as trapping, I used a small juice glass with some squid at the bottom that I propped up against a rock at a 45 degree angle. They go in and can't go out because the glass is slippery. First two nights I caught my hermits and emeralds, but after the third night I caught the Mantis Shrimp that had taken out two brand new clowns I had in the tank.

 

[Jvesche20]

Dang! How big is this Emerald Crab? I have two in my 32G Biocube and I rarely see them and I have not lost a fish to them. Mine are tiny; about 1.5 inches. Makes me wonder how long term they will be.

As far as trapping, I used a small juice glass with some squid at the bottom that I propped up against a rock at a 45 degree angle. They go in and can't go out because the glass is slippery. First two nights I caught my hermits and emeralds, but after the third night I caught the Mantis Shrimp that had taken out two brand new clowns I had in the tank.

Did you purposely put the clowns in the same tank as the mantis shrimp? or was he a hitch hiker?

 

[Shredder99]

Mantis was a hitch hiker. When I put the first corals in the tank, I didn't dip the corals. A few months later I would hear popping sounds when I was near the tank late at night. I assumed it was something mechanical (I was a noob and still am to some degree). The clowns went in and disappeared within 24 hours without a trace. I thought that they might have jumped out, but after mentioning the popping to my guy at my LFS, he brought up the theory on the Mantis Shrimp and gave me the tip on how to catch it.

 

[WallysWorld]

I used a plastic water bottle with bait food in it. Crab crawls in and you can scoop bottle out before it has a chance to scramble to another location. It does require you to be some what observant and ready to move when caught in the bottle.

 

[Jvesche20]

Mantis was a hitch hiker. When I put the first corals in the tank, I didn't dip the corals. A few months later I would hear popping sounds when I was near the tank late at night. I assumed it was something mechanical (I was a noob and still am to some degree). The clowns went in and disappeared within 24 hours without a trace. I thought that they might have jumped out, but after mentioning the popping to my guy at my LFS, he brought up the theory on the Mantis Shrimp and gave me the tip on how to catch it.

Thats insane do you have any pics of the mantis shrimp?

 

[Shredder99]

I don't. When I saw it in the glass, it's appearance freaked me out and I just wanted to get it out of the tank so it pulled the glass and flushed the thing post haste. Funny thing, there was a report on the news last night that sanitation workers are disappearing when they go down in the Denver sewers for inspections.

 

[Jvesche20]

I don't. When I saw it in the glass, it's appearance freaked me out and I just wanted to get it out of the tank so it pulled the glass and flushed the thing post haste. Funny thing, there was a report on the news last night that sanitation workers are disappearing when they go down in the Denver sewers for inspections.

Ah, I would have taken it to my lfs and tried to sell it. Not sure if they would buy it but oh well. Funny story!