Do I have a mantis??

[daveinkeswick]

Hi everyone

I placed some extra LR in my tank last week and I got a small gorilla crab as a hitchhiker(about 1" dia, hairy, with large claws, body was brown and legs were stripy). Other tank inhabitants are:
2 perc clowns
6 blue-leg hermits
6 turbo snails
1 brittle starfish

Recently I have been hearing knocking sounds (like someone is knocking on the door), there are like 3 to 4 knocks in a row and then nothing for a long time. They only happen when the tank lights are out and I might only here them twice in a 4 hour period.

Anyway, today I was looking in the hole that the gorilla? crab lives in and I spotted that the crab hadn't moved since the previous day. I pulled the rock out and shook the dead crab into a bucket, it fell out of the rock in pieces, so I'm guessing something smashed it up. Unless its possible for it to decay like that within a 24hr period??
As I shook the rock I saw another creature inside the hole, it was about the same size as the gorilla crab and I couldn't make out a shape so have no idea what it was. anyway, it scurried deep inside the rock, this particular piece is full of deep caverns and tunnels!!
I've put the rock back in now.

Any ideas??
Mantis or Pistol? if either?
Incidentally the crab did not appear to have been eaten, there was still a lot of flesh left.
If this is a mantis, I have the oppurtunity of a loan of a small snowflake moray(10" long), would he get the culprit??

Thanks very much for your time guys.

Dave

 

[Uriel]

Well, there are a lot of folks on here who can give advice on catching whatever it is.
I know that if a 10" eel came near my G. Ternatensis, you'd have a dead ell, so be careful with your friend's/the LFS eel. Some mantis are rather pugnacious. there are all manner of cases of them killing eels,triggers, octos etc...

Good luck, and if you catch it, someone here will want it, maybe give a good trade etc..

-Ron

 

[EMG]

If you isolated that creature to that rock or at least think you did you should have put that rock in another tank or bucket until you found out if it was a Mantis or not.
I would never have put it back in there.

 

[daveinkeswick]

well the creature that was crawling in the rock turns out to be another crab of exactly the same type. I hope they've not had babies!
I heard the usual burst of 3 clicks last night but couldn't spot anything and my snails and hermits are accounted for. I think I'll have to wait a while to be sure that there is a mantis in there.
Any ideas on how I can make it show itself??