Naturally exterminating mantis shrimp?

J

JC Pollman

Premium Member
I am reasonably confident I still have a couple of mantis shrimp in my tank. I have not seen them, but I hear them all the time. I recently caught one when he exposed himself trying to steal some food and I saw which rock he scurried back to. I dunked his rock into fresh water for 5 minutes, let it sit exposed to the air for 10 minutes, and he finally dragged himself out and died. I am not keen on using this procedure for the rest of the rocks as I believe I will likely kill-off more than just the shrimps.

My question: If these shrimp are so hard for us to exterminate, how come they are not over running the reefs of the world? Something must be controlling their population. Other than octopuses, what else eats them? It seems to me that we should be able to put something in our tanks that will eat these buggers. I have read that some folks have had success with some moray eels, but the success rate does not sound encouraging.

Thoughts?
 
2-liter bottle with the top cut off and inverted. Put food in the bottom. Shrimp goes in, can't come out. Remove trap containing Mantis from tank. Do a little dance then have a beer :D.
 
Traps? Been there and done that for 3 months. They never seem to come out of their rocks - though I have caught many brissle worms and crabs.

I have 2 clown fish that know the mantis are there: they never swim lower than 5 inches from the surface. I also lost a small 6 line - he might have jumped, but I have never found the body.
 
get rid of the clowns. have someone hold for you or something. get a big trigger or two let em loose in the tank, they clear em out in no time.
 
Getting some large triggers to exterminate a couple mantis sounds a little overboard, eh?

I have read up on Mantis removal, and the traps seem to work fine for most people. Are you placing the traps near the hole where you know the Mantis resides? They usually wont venture far away from this hole, as evidence with the fact that your clowns are still alive.

Also, if you know exactly which rocks they are in and the holes they are hiding out in, then you don't have to dip the whole rock into freshwater. Put the rock in saltwater, and then use a turkey baster or syringe and squirt freshwater or carbonated water into the hole.
 
2nd dibs!!! Man, I never catch these threads fast enough!:D

Seriously, this link may help...

Click here for trap ideas!

But, If you do catch one I would be glad to pay for shipping plus a little for your trouble if necessary....PLEASE!
 
Aside from the fact that I cannot comprehend why anyone would want to eliminate stomatopdos from their aquariium, I can provide you with a bit of information. A stomatopod is not just a stomatopod, so I will limit my discussion to Neogonodactylus bredini and N. wennerae, the most common New World mantis shrimp showing up in LR.

In some areas, stomatopods do reach very high densities. Our studies on grass beds in Panama and Florida found densities of over 5 animals per square meter and it is not uncommon to find a dozen or more stomatopods in one, basketball sized piece of coral rubble.

The single most important limiting factor on population size is the availability of suitable cavities. Many species do not live in live coral but are LR specialists - typically preferring coralline algae encrusted coral rubble. Where rubble is sparse, every piece contains one or more stomatopods.

However, stomatopods can also be prey limited. We have shown that even a modest increase in stomatopod density can rapidly decrease the numbers of appropriate sized snaiils and hermits. On the flip side, adding snails and hermits to an area can increase numbers of stomatopods IF their are appropriate cavities.

Stomatopods are territorial and often will try to keep other individuals out of their immediate area. Because of the tight fit of the cavity entrance to the animal, you can have coesisting animals in one rock, but if they are near the same size, this usually does not happen. One will kill the other. On the other hand, a small animal will not attack a bigger resident in a large cavity and a large animal can't get into the cavity of a small one.

These stomatopods usually make several excursions a day away from their cavities to find prey. This exposes them to predators such as fish. A fish similar in size to a stomatopod doesn't stand much of a chance killing it, but larger predators such as 6 inch plus triggers and puffers that can fit the animal in its mouth are easily able to kill it. Herons and egrets are also effective predators. I've seen an individual heron take 4 stomatopods a minute during a low tide on a grass flat.

For predators to feed on stomatopds, they must either be able to catch them in the open or get them out of their cavity. This obviously isn't easy and aside from octopus, most animals small enough to stick their head into a cavity can't deal with the offensive and defensive weapods of the mantis shrimp.

Roy
 
Mantis shrimp are not overrunning the reefs because everything eats them. In out tanks the fish are small, only a couple of inches but in the sea the majority of fish are about a foot long. At night when they hunt they are in a very precarious position. Fish treat them like any other shrimp. Lunch.
 
I also have a mantis in my tank that I've been trying to catch for over a month now. I've tried many variations of the "inverted coke bottle" trap, but it's never worked. My cleaner shrimp and wrasse manage to squeeze in every time and get trapped. I've also tried dunking the suspect LR in freshwater for about 5-10 mintues, with a power head shooting water thru all the cavities..no avail. I've lost 2 fire fish in the past...but no other fish casualties in the last month...I guess I've given up for the time being. The mantis is about 1.5 in. I've seen him moving about.
 
Got 'em

Got 'em

I was doing my nightly checking of the tank last night when I noticed one of the rocks on top had a lot of sand on it. This is very odd. On closer examination, there was a HOLE in the middle of the sand! I quickly yanked the rock out and put it in some fresh water. A thorough examination of the rest of the tank and another rock had sand. It also came out. Neither rock ever yielded a mantis, but this evening has been click free!

So, for all those wanting to find your mantis shrimp: look for the exclavation signs.

JC
 
!!! I Finally Caught IT~!!!!

My yellow headed Jawfish got pretty tore up the last two days...I came back from work and found it floating around with the other fish picking at it.....I placed the jawfish in a specimen tank, and began my search for the evil mantis. It took me a couple of hrs, with removing and "squirting" all the holes in various rocks with a syringe full of freshwater, but when I found him, I saw his tail sticking out of one of the holes....I gave it a good squirt, and he just fell right into my bucket!!! yup...it's a smasher.
 
The jawfish may have been tore up by something, but it is unlikely that a 1.5 inch smasher would have done anything but hide from any fish (especially a jawfish). In a 29g tank (even with a deep sand bed) a jawfish can stress itself out pretty quickly all on its own...

'Piercers' pierce and eat fish...

'Smashers' smash gastropods and crustaceans for food...
 
the jawfish is about the same size....and had recently switched burrows to one which was under the suspect LR....less than 1 day later, he got all tore up. =/
 
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