I have heard popping in my tank before

[Gregsgsr]

I just bought a pistol shrimp which i knows makes a poping noise in my tank, but before this I have heard a similar noise. I was wondering i might have a mantis in my tank. I have had some fish just disapear in my tank, but they were leopard wrasse which are hard to keep. I can never find any remains, the guy at lfs says the crabs eat them... I was wondering if anyone have any ideas how to find one of these buggers or how to get them out...

 

[jecarl2]

I've had one in my tank for 2 years and have never seen him. I have not lost any livestock to my knowledge. I do want him out of my tank, whats the point if i cant see him anyway.