First Mantis, dunno if he'll make it.


New member
Howdy ya'll...
I've been thinking about getting a Mantis for awhile now, and yesterday while perusing my LFS, they had a beautiful, about 3 inch Mantis (I have no idea of the exact species, but it came in with some Florida liverock.).
When I inquired how much it was, the guy at the LFS freaked a bit, and was suprised that I would actually want such a vile and evil creature. He gave it to me for free, so I went ahead and took it. He's now in an Eclipse 3 gallon acrylic tank with about 2 inches of crushed coral substrate, about 1 pound or so of smaller chunks of live rock that I fashioned into a crude cave for him.
However, ever since I put him in (Over 24 hours now) he's just been laying on his side or back, fanning his swimmerets constantly. I thought this might be osmotic shock as I admittedly was too excited/nervous/etc to properly acclimate him, but after 24 hours the osmotic shock should have either worn off or done him in, I would think.
About an hour ago I put in about a 4 inch piece of PVC pipe to see if he'd go into that and use it as a burrow, but he's still just laying there fanning the swimmerets.
I put in some mysis shrimp, and he ignore that, so I siphoned it back out.
For water, I pulled the water out of my 200 gallon reef system to be sure the water was well aged. I've done one, and plan on doing about 50% water changes with aged water until the biowheel becomes active.
I guess that's about it. Anything I should do beyond what I've done to make sure the little critter makes it? I've pretty much reached a sit and wait stage to see how he does, but I figured I'd ask some of ya'll that have more experience with Mantis to make sure I'm not missing something critical for their survival. Admittedly, I don't think he has been receiving the best of care since he was extracted from the live rock at the LFS, and put in a little cup to show people the horrors of the evil Mantis. To keep my own conscience clean, I keep telling myself that even if he doesn't make it with me, he's better off than sitting in that little betta cup waiting to die at the LFS... Oh well...

Thanks in advance for any assistance! So far if nothing else it's been worth it for the look on the LFS guy's face when I told him I wanted the Mantis... :D
Sounds like the little guy had a rough experience getting from the ocean to your house.

What temperature is his tank?

Is there any biological filtration other than the pound of live rock?

I'd leave the light off and observe for a few days.
Currently the tank water is in the mid 70's, but only because the tank (3 gallon eclipse) is in a warm room (My computer room, I'm a computer nut, and there are 14 computers in the same room)
I was afraid of putting in a heater, afraid he'd smash it, is that a realistic fear, or should I pick a small heater up on my way home from work to keep the temp a more stable upper 70's?
The tank has a biowheel, but it is brand new. I would have preferred to cycle the tank properly, but it was either take the Mantis and put him in it now, or leave him to fend for himself at the LFS. To help out, I've been doing roughly 100% daily water changes (Split into 2 daily 50% changes), but the water is well aged, I've been taking it from my reef system. Now that my initial panic has subsided, I'll most likely cut back on the amount of water changes.
I'm thinking there's something about the way the tank's setup that the Mantis doesn't like. He's been sitting under the water intake for the biowheel, all curled up most of the time. I tried to gently nudge him towards the rocks and small piece of PVC pipe last nite, hoping he'd figure out it was a home for him. As soon as I stopped nudging, he seemed to straighten out, and run across the tank in a perfectly normal manner, looked fine, but he headed right back to the empty corner of the tank and curled back up. I dunno...

He didn't make it... Just got home from work, and he's pale, motionless, and starting to stink... :( :(

I think I'll leave him in there to cycle the tank properly, than begin my quest to find a healthy Mantis in earnest... Thanks for your help.....
You should be afraid of the mantis breaking a heater, because, given enough time, it will. They break heaters a lot more easily than they break tank glass. I asked Dr. Roy Caldwell about this and he related some of his heater experiences in the 30 years he has been keeping stomatopods. You can read his posts at my website:

I'm guessing at least some of those 14 computers must be on all the time. If they keep the room at a constant temperature anywhere from 76-84 degrees F I wouldn't worry about adding a heater.

The water changes are a good idea (using the reef water). I think you should probably add one or two small chunks of live rock. Keep doing smaller water changes (25% or so a day) for the next week or so.

The curling up behavior you are describing sounds like a mantis that is having a hard time adjusting to a new environment. This is why it is not eating. It won't start eating until it likes its environment. If I were you I would add one or two small rocks, keep the lights off, and wait a few days.

Mantis are burrowers and need to be able to dig down in the substrate several inches to make their burrows. A deep sand bed would probably make your mantis feel more comfortable. Sounds like you are planning on keeping the little bugger long term if he makes it. I would recommend a 4" or deeper bed of aragonite sand. Don't get the finest grade of sand, get a medium or large grade. They dig a lot and can make a big mess if the sediment stays suspended in water.

Your mantis also may have been damaged during his shipment with the liverock. If that's the case, you can't really do much except wait it out.
Ah well, at least you tried. Let me know where you get your mantis from, they seem a bit hard to obtain. I'm curious if FFExpress is still selling them.
Sorry about the loss...i've had my share of too-weak-to-live when-bought mantis shrimps...when one of them ignores a potential home you know things are pretty grim...

Any idea whether some mantis shrimps (the big colorful ones as opposed to the 'pest' found in liverock) are caught using poisons?
Well, I haven't bothered to contact them, but I couldn't find Mantis listed anywhere on FF Express' web site.
I'm in pretty good with the head salt water guy at a decent LFS near me (The one where I got my first try from) and he's in contact with the people that ship the Florida live rock quite frequently. I'm gonna try to swing out to his shop this week/weekend and see if he could ask the people who sell the liverock to scoop up one fresh from harvest and ship it to him for me. It's worth a shot, but as I'm looking for a smaller Mantis, this might be my best shot at getting one, and if they ship it soon enough from when it's discovered in the rock, hopefully a healthy one this time...

I'll keep ya'll updated on my progress... I'm not in too much of a hurry, I'm gonna give the tank some time to properly cycle while I can...