Pistol Shrimps

As I don't have any fish in my tank, just cuc, why would it still be cycling?

 

The clicking noises are probably a mantis. As for the ammonia and nitrite, have you taken a sample to the a LFS to verify those readings?? IF they are correct your tank did cycle again. Could have been from the large die off you had.

 

If the clicking is pistol shrimp, you shouldn't have a problem. If it's mantis, good luck catching it lol.

 

Watch your fingers if you suspect a mantis, they are dangerous. Ammonia and nitrite are extremely toxic to fish and invertebrates. It will come under control given some time for the necessary denitrifying bacteria levels to build. Perhaps a few weeks. Mantis shrimp are ridiculously good hunters with senses beyond our understanding. It will be very difficult to find and remove.

What size is your tank?

 

what size tank and how many pounds of live rock do you have?

 

Another way: throw an injured crab in the tank. If it's a pistol, you won't see anything; it won't come out regardless. If it's a mantis, you'll see it run up to the crab, punch it a few times, and drag it back to a cave.

 

Good call. Kinda sucks for the crab if you do have a mantis though.

 

I have plenty of the gorillas to give, if anyone needs to test for a mantis problem ;D

 

My tank is 125 litres and I have approx. 20-25 kilos of live rock.

My tank was fine for the first 8 months, but then I noticed the hermits were gradually reducing in number. What I don't understand is if I had an agressive predator (such as a Mantis, or maybe a Pistol, who must have arrived with my LR) surely it would have started killing much sooner.