Hitchhiker Advice

[maxvitek]

There are a variety of hitchhiker crabs in my 4 month old 75 gallon reef tank. Live rock from Bali. Removed two, a hairy one with predatory looking claws, and a grey one with predatory looking claws and red eyes (this one was remodeling the tank nightly). There are two more small ones of the grey variety. There are also two more hairy ones, but different with smooth, scooped claws. I believe that I will need to break down the tank and chase out the crabs. My questions are: Should I remove all of them to the refugium? If the crabs prove difficult to extract from a given rock, should I use the club soda method to encourage them? There is also a cracking sound from time to time, the occasional hermit crab shell with a hole in it, and signs that someone is excavating the rocks near the base of the rock wall. Any worries there? Thanks for any advice you can offer. Have a variety of zoos, platys, soft and leather corals which seem happy and oblivious to the drama for the time being. Also three fish, two springer damsels and a six-line wrasse, all of which are happy and healthy. Thanks again!

[twelvejewelz]

The cracking sound sounds like it could be a mantis shrimp. If thats the case i would remove it or it will destroy your tank.They eat snails, crabs, fish and just about everything that you would probably want to keep. After 3 years of having my tank set up i am now noticing that i have a hitch hiker crab as well. Im going to do the "shrimp in a glass method" to try and remove it. Just get a raw uncooked shrimp and put it in the tall drinking glass when the lights are out, and put it near the hole where you think the crab is located. The crab will go for the shrimp and not be able to get out of the glass. Put the glass on a tilt not straight up. good luck.

[maxvitek]

Thanks for the quick reply! I should note that I tried that same trap several times. It works really well to catch hermits and the emerald crab I have. But I feel like it gets so busy in the bottom of the trap so quickly that the more evil and shy crabs are persuaded not to indulge. Do you think I'll have better success if I persist? If I break down the tank and inspect each rock, would I be able to catch a mantis?

[twelvejewelz]

Ah welcome to reef central theres alot to learn here im sure youll enjoy :) .You may want to keep at it im sure youll get them but you can always take the rock out thats up to you of course. If it were me though id stick to the traps but thats just because im to lazy and i like my rockscape and if i started messing with it im sure id never get it back exactly the way i want it haha. Are you doing the trap an hour or more after the lights go out? You want to give it enough time for the "night time" animals to be comfortable to come out.Im sure you can get the mantis if you can isolate the rock and remove it. Some people use club soda in their hole or a fresh water dip and the crab/mantis will come swimming out .

[maxvitek]

Ah, here may be a point that I missed during my lengthy period of lurking around this site. So far, I've baited and set the trap before the lights go out and then left it overnight. Is it better to bait and set the trap after the lights go out? That makes sense to me.