Sea Urchins


Does anyone know if sea urchins make a popping noise? I have had live rock in my 55 since Oct. I found a mantis shrimp immediatly and got it out. But I still keep hearing popping off and on. By the time I get to the tank it stops. I've looked day and night with a flashlight and cannot find another one but I do have an urchin that came with the rock. This is driving me nuts!


Active Member
I know of no way the urchin could be the source. My guess is you have another mantis or you have a pistol shrimp (both are likely posibilities). If you are unfamiliar with pistol shrimp, do a search. They actually have a faster claw than the mantis, so fast it creates a shock wave which it uses to stun it's prey. However, pistol shrimp are harmless to all normal tank inhabitants and don't need to be removed.