Something wrong with my mantis

[Ken2001]

I've had an M. wennerae (sp?) for about 8 or 9 months now in a five gallon nano. For the last few days I've not seen it, and assumed it was in the process of a molt (I've seen it molt at least twice before, and assume its done so other times that I've missed). Anyway, I finally got worried that I'd not seen it at all for the better part of a week, which is unusual. I pulled apart its burrow and found it flailing around on its back, its swimmerettes going like mad, but not able to propel itself properly and not able to stay right-side-up. One of its smasher appendages is cocked at a funny angle, almost fully extended.

It is a brighter shade of green then usual, so it may have just molted, but I'm pretty worried that it's in real trouble. Does anybody have any idea what could be wrong with this mantis? I've noticed in passing while reading the list that these animals can suffer from bad molts, but I don't see anything about this on the Lurkers pages - if there is a FAQ out there on mantis ailments and diseases, I'd appreciate it if someone could point me to it.

Thanks,

Ken

[Ken2001]

Just looked in on it a few minutes ago. The mantis is laying out in the open in the tank, kind of writhing around, and trying to move, I guess. All of its limbs seem to have some level of mobility, but a couple seem sort of deformed, as though they're not fully developed. At this point I'm guessing the animal isn't going to pull through, but I'd still really like to know what happened.

Ken

[reefrancher]

Tell us more .. how is he now?

How big is his tank and when was the last water change?

When was the last time he ate and what was it?

I hope he pulls through.

[Ken2001]

Hi Steve,

I didn't know you were an XTC fan.

The mantis is in a 5 gallon hex, w/ a carbon, mechanical, and bio-wheel filter - one of those little exclipse jobbies. I probably haven't changed the water in a month - I would have done so yesterday, but we had some rain yesterday so I didn't want the NSW to be contaminated by run-off - I'll be getting some tonight for a change. I typically feed the mantis periwinkles and mussels that I collect at low tide, but lately have been giving it krill. Last meal was about 4 days ago - I didn't see it come out to get any, so I held off feeding until I saw Mantizilla again. Finally, as I said above, I pulled its burrow apart yesterday and discovered it unable to move properly. BTW, I was just looking at it again a few minutes ago, and except for the left smasher, which is fully extended and sort of withered, and one other leg that is kind of cocked out at a funny angle, all the other limbs look normal. However, the mantis' movements are anything but normal, as it flails around on its back and side. I wish I could figure out what the problem is....

Any ideas?

Ken

[reefrancher]

I would do a battery of tests on the water - just in case. Check salinity first. If the parameters are out of whack I would do whatever necessary water changes in stages so as not to shock the critter to death.

[AttackDonut]

I have seen this before (sadly, to one of my own), I *think* it was a molt gone wrong....

..in other words, he was trying to molt, but couldn't shed his old skin, and died pretty quickly because of that.

I've read (here on this board) that a lack of iodine and some other trace elements can cause this.

[Gonodactylus]

The molt failed as Attackdonut said. It will not recover.

I don't know where the iodine story came from, but I know of no evidence to support it in stomatopods. Normal concentrations seem fine.

I have found that nitrate build-ups can cause problems, particularly in small tanks. It is a good idea to to a partical water change on a regular basis - say 25% each month.

[Hwarang]

What does it mean to fail a molt?

The old shell detached improperly, taking flesh with it?
The new stuff forming under the old shell was deformed?
The old shell won't come off?

[Gonodactylus]

Basically the old cuticle did not separtae properly from the new one developing underneath or the animal was too weak to spit the old one and pull free. When a stomatopod starts to molt, it resorbs minerals from the old cuticle. Also, break lines begin to weaken and dissolve. The most obvious are on the midline of the dorsal thorax. A few hours prior to the molt, you can often see these lines open up. The animal then takes on water and uses its muscles to greatly increase the hydrostatic pressure inside - liiterally rupturing the weakend areas. It then pulls itself out. A healthy animal can molt in a couple of minutes, but if the old cuticle does not lift off the new one, the suture lines don't weaken, or it cannot generate enough pressure to split the old cuticle, it fails to shead all or part of the old cutlice. Death can be for several reasons and can take different amounts of time, but most animals don't make unless the problem is simply one of pulling free the raptorial appendagg

Roy

[Ken2001]

Damn. I was afraid of that, but I really didn't understand what a failed molt was. I'm really disapointed to find out it's not something that can be reversed, but I guess I'm not totally suprised.

Thanks Roy, and Attack, for the info. As far as the causes, I do know that when I last changed the water, about a month ago, it was a 50% w/ NSW, but in that small tank, I guess the nitrates can build back up quickly.

Thanks again,

Ken

[Hwarang]

thx doc!

[ReefMagic]

According to your first post, the only one I read ;), that is the same thing that my mantis' have done in the passed. I don't know how it happened to all of them. but it did. I've had 4 so far, and I am still afraid to try for another one, because i dont want to kill it.

[Ken2001]

Well, Mantizilla is still hanging in there. It's managed to figure out how to walk, sort of, though if it goes too fast or too far it does end up falling on its side and then flipping over onto its back. It still eats whenever I toss a piece of mysid into the tank, and will even try and swim it down. Still, I often see it just laying on its side in the tank, but just when I think I'm going to have to send it on to the big porcelain whirlpool in the sky, it jumps up and starts patroling the tank again. I wonder if there's any chance it can pull through? How long after a bad molt do mantis' usually die? Is five days and still going typical?

I think it knows I'm bringing in a peacock tomorrow (in another tank) and is PO'ed. On the bright side, the big hermits in Mantizilla's tank, the ones that it couldn't kill, or just was too well fed to bother with, are going into the peacock's tank, so no more food competition for Manti.

Ken

[Ken2001]

Time for another quick update - Mantizilla is still kicking. He's found a new way of getting around - essentially he just lies on his back and kicks like hell. It actually works pretty well, because he just scoots around on his back like a kid on a sled. I feed him every other day with some shrimp - takes a little longer to find the pieces, but always eats in the end. At night, he tries to get into his lair/cave - usually he ends up half in/half out, which looks pretty funny. I did take all the hermits, including the really big one, out of his tank, and sent them to stay with the peacock. Needless to say, his old mates are history.

Ken

[T-T-Trigger]

wow, that is great. I hope he continues to fight through it, good luck.

[smasher]

Had one do the same thing that finaly pulled threw. Hope he makes it, keep us posted.

[Ken2001]

Mantizilla died last night. Just couldn't pull through.

Ken

[O'Coralman]

Ken....guess he'll be hanging out with Big Ben. Sorry to hear the news: ..........Steve:(

[dapel]

Sorry to hear the bad news. Great effort on your part tho.

-Dan