How catch crab

[aygamisou]

Hello all, I am new here to these forums. I am also new to aquarium keeping. I recently got a live rock from friend, and I find crab in it last night. It only emerge in darkness, so I cannot get a picture. But after searching, I think he is red mithrax crab. I also discover he is dangerous to my tank, but I cannot catch him. I have try using soda bottle with bait, but he does not take it. Does anyone else have ideas? Thanks you!

[DiazE]

Take a plastic water bottle, cut off the neck and invert into the other half. Make sure to tie both ends so it doesn't come apart.
Put some bait in it and try to lie it close to were it hangs out. Tie a string on the bottle so you can pull it out as soon as it's in there.

When you catch it, eventhough it might be a mithrax, post a picture of the sucker for I.D. purposes in case it's a "good crab" you can keep.

[ddinox64]

I chased my Emerald onto the sand bed where it moved pretty slow then just used a net. I read somewhere to put sinking food in a tall glass, lean it against the rocks at an angle it won't be able to scale when it goes inside for food. I caught my Peppermint in two seconds doing that. But I wanted the Emerald.

[650-IS350]

Get a large or tall shot glass, place it at night where your know the rogue crab hangs out at and place it to the side of the rock. Crab investigates, slides down for the food but can't get out as the glass is smooth. Takes a couple times to get the crab.

[arredondojason]

toliet seats are a good way to catch crabs as well

[arredondojason]

ok all joking aside is there any corals on the rock this crab lives in. if not pull the rock out put it in a cooler for like 30 min to an hour then open it up he will be on the bottom of the cooler you can put a shrimp or something in there as well to help lure him out then if he is not near the rock pull the rock out you dont need to put water with it just put the rock in there and it should work.

[vlim13]

Get a large or tall shot glass, place it at night where your know the rogue crab hangs out at and place it to the side of the rock. Crab investigates, slides down for the food but can't get out as the glass is smooth. Takes a couple times to get the crab.

+1 on this. I caught crabs twice :D with this method. The first time worked like a charm, but didn't catch the big one that I wanted. It took a few more tries, and 2 days of not feeding for the bigger gorilla crab to show himself. It wasn't even scared of me. I got a glass, put a few pieces of squid in there, and then set them in the tank. Had to play with the angle to get to where the crab could climb in. But once I got it in the right position, it took literally 30 seconds for him to climb in, and I just tipped the glass back upright.

The big one totally trashed my sandbed. He dug tunnels under all the rock in my 14 gal, and pretty much ruled the tank. Now the smaller porcelain crabs come out, and I hear more snapping sounds from a yet to be found mantis.

I would have left the gorillas in there, but they started eating some of my euphylia and zoanthids that I put in because I didn't get to feed for a couple of days. Now the two main culprits are in my fuge in a larger tank, and I feel better about adding a small fish or two.