Could my pistol shrimp have gone rogue?

[TL1000RSquid]

A couple weeks ago it started, not long after adding a pair of bonded pistol shrimp, and a couple nice pieces of live rock.. Since then a mass grave has appeared in the corner of my tank, 20 shells or so, nassirus, turbo, astrea, nerite all nice sized ones belonging to snails or full sized hermits.

I've kept many pistol shrimp before and never had anything like this happen and if they did kill anything the shell went down the hole not stacked in the corner. Am I looking at an unknown hitchhiker in the rock or could the shrimp have done it? Whatever it is seems to be averaging 2 nice sized snails/hermits a night as a meal.

 

[cloak]

I've always thought pistol shrimps were blind as a bat. If so, you probably do have an unwanted hitchhiker in your tank. Keep your eyes peeled.

 

[TL1000RSquid]

Yeah I believe they pair up with gobies to use them as their eyes/early warning, I don't know if it makes a difference these are Bullseye Pistols which usually don't pair with gobies.

Shells are intact so only other thing I can think of is a spearing mantis, but no fish are missing and I do have a couple small wrasse and gobies.

Do mantis throw all their empties in one pile?

 

[cloak]

Probably not, but the lair could be close. You might want to either purchase a trap online, or build one yourself and set it in that area. GL.

 

[Betta132]

Going by my experiments with shadows, pistol shrimp can tell the difference between light and dark. Aside from that, yes, they're blind.

The pistol didn't do that. If it did kill stuff (very very rare) it would keep the shells for building material.

 

[Calappidae]

Bullseye pistols can be a little more oppertunistic torwards the mentioned. They won't hurt fish or shoot at anything, however they'll still kill something the same way a peppermint shrimp or like would. I find it unlikely but possible.

 

[Betta132]

But even if they did, the shells would end up in the burrow or around the entrance. Pistol shrimp don't throw away perfectly good building material.
Even when said building material is still occupied. Mine used to steal hermit crabs until he got tired of them wrecking things when they crawled back out.

 

[Fredericks]

I doubt that it was the pistol shrimp. Im betting on a hitchhiker.

 

[TL1000RSquid]

No luck finding any culprit yet, going to try a freshwater dip on the rock closest to the grave.

 

[wcarterh]

I'm curious if you found anything TL? What about setting up a video camera for a night to record?

 

[TL1000RSquid]

Still haven't caught anyone, pretty sure its not the pair of shrimp they split up and one moves to opposite side. I did dip the rock in some fresh RODI water and couldnt find anyone living in there either.

Video cameras a good idea have to see if it has enough memory, and figure out how to keep the moonlight on all night on the radion, no nightvision in the camera i have.

 

[Betta132]

Make a mantis trap with plenty of vent holes, put a snail in the trap, and see what happens?