large killer crab

[Cassius]

we have a crab about the size of a silver dollar in our 65 gal tank.
I have no picture of it because it only comes out at night. I have
seen it only a couple of times but for several months we have had problems keeping snails and other cleaner guys in the tank.
Now it is killing fish as well I think. We have only one fish that has been able to stay away from it a clown fish I think because he sleeps up by the filter and it cant get to him. the fish always disapear during the night without a trace. We had a shrimp that was killed but not eaten but was really messed up. Thats when we figured out what must be happening. My question is: How can we get rid of him. We tried a trap it but he didnt fall for it. I really hate to take everything out to find him But if i do whats the best way to keep the tank from dying or having to start over? Any help you can give me would be great!! thanks

 

[Fat Man]

Get a large glass and place a piece of raw shrimp in it. Lean the glass at a steep angle against your rockwork. The glass must be large enough so the crab can't climb out. When it decides it really wants that piece of shrimp it'll crawl in and be stuck.