Peacock mantis shrimp died, don't know cause

[Cimmerians]

I had a juvenile peacock mantis shrimp for awhile, perhaps almost two months. He died the other day, and I'm still having trouble figuring out exactly how. I tried to feed him every two to three days, but after his first feeding he almost always rejected it. He went through a tank move to one with more rocks for him, and after that I thought giving him a live chromis might get him eating (I know peacock shrimps are smashers, as he also got a snail he never ate). During the period of no eating lasting the majority of the two months, he manage to kill and (probably) eat two hermit crabs that I left in the tank when I originally cleared it out for him. Within 12 hours of dropping the chromis in there it was gone, and my mantis may have been disturbed since I moved around his rocks to find the body before it taints my water. Couldn't find one, so I assume he ate it. About two days later he died, and I'm suspecting it may have been his lack of molting during the whole stay he had with me. Anyone know of any other causes that may have killed him?

(If this bit of information contributes anything, he had a really dark green color instead of a vibrant emerald green, and I assumed it was due to poor diet)

[Martini5788]

What were you trying to feed him? Sounds like starvation.

[Martini5788]

Also, from my understanding their colors vary greatly, and doesn't mean they are unhealthy, just genetics

[Cimmerians]

I tried feeding him cut bits of frozen shrimp. I know they're picky but he accepted it the first time

[Cimmerians]

I was actually afraid he might have been starving, which is why I gave him the chromis

[BuzzPion]

Sounds like stress and starvation to me. All that moving around and rearranging. Also, poor choice of food. No real variety. A chromis for a smasher?

[Cimmerians]

He had a snail in there that he wouldn't eat

[EI Gringo]

Your food was fine, shrimps, fish, hermits, snails, everything should have been fine, you weren't doing anything wrong and moving his tank probably wouldn't bother it. It maybe needed to molt but couldn't loosen from its shell, or maybe an ammonia spike from the chromis death or even just a poorly cycled (immature) tank.

[Calappidae]

What was it's burrow like? If it's moving rubble, it's trying to close up in preperation of a molt.. if you didn't provide a proper burrow, chances are you denied it of proper molting conditions, delaying the molt, and a failure in having the molt. They will also reject food during this time.

Also color isn't an indication of anything.. stomatopods vary in color depending the depth they were born. The higher they are, usually the more green.. whereas the deeper they are the "reder" they can be.

[Cimmerians]

When he was moved to the new tank with more rocks, he had a nice cave that was hard for me to see into but he spent a lot of time in it. I heard smashers liked rock caves, and he seemed well off in there. When I re arranged the rocks looking for the dead chromis, however, I had to take apart his cave and rearrange his entire set up, which I kinda feel bad for. But I just couldn't have a dead fish rotting in there.
And my mantis didn't move anything around, he was still a juvenile and most of the rocks in there were probably to massive for him to move.

[Cimmerians]

Forgot to add, the tank never had any ammonia issues from what I could detect, but I've been having trouble lower the bad nitrate levels circulating around. Even when I did water changes (20% ones to 40% ones) it still had bad levels.

[Calappidae]

Most of us use PVC pipe for their burrows, usually anything made from rockwork alone isn't good enough. If the burrow isn't perfect, it's faulty.. and if it wasn't a perfect smooth U-shaped burrow that has an area covered in complete darkness, chances are the animal is too stressed out or unable to molt in proper conditions.

I wouldn't blame it on ammonia or nitrates, the worst result of high nitrates would be shell rot.

[Derrick12]

Ur mantis may have buried some of his food and after u went looking for the chromis u may have stirred up the tank to a toxic level
Especially if the thing was in poor health.....u said juvenile so how big was it. U prob would be surprised at how little food the mantis would actually eat at one setting
If was over feed or trying to feed a lot it could have buried food. They do that

[Kharn]

I experienced a lot of gorging and snacking by my mantis shrimp (specifically the smashers) they were always given more food then they would consume but they would never bury it just hold onto it and keep it close slowly picking at it through the day, usually after a good day of picking they would toss it away (never bury it) which made it easy for me to remove the scraps.

They may have small "bellies" but they burn through food FAST, some can go up to a month without food!

I remember reading about their feeding behaviours in the wild...

If the mantis finds/acquires a large meaty food item then it will do for the day and not really come out to seek out more food.

If its only small portions then the mantis was seen entering and exiting its burrow through out the day over half a dozen times but each bring back was a 'small' food item.

It makes sense for such a high energy utilizing animal to burn through food basically as often as they can acquire it, like a V10 car engine sucking down fuel like crazy!

[Martini5788]

Originally Posted by Kharn

I experienced a lot of gorging and snacking by my mantis shrimp (specifically the smashers) they were always given more food then they would consume but they would never bury it just hold onto it and keep it close slowly picking at it through the day, usually after a good day of picking they would toss it away (never bury it) which made it easy for me to remove the scraps.

They may have small "bellies" but they burn through food FAST, some can go up to a month without food!

I remember reading about their feeding behaviours in the wild...

If the mantis finds/acquires a large meaty food item then it will do for the day and not really come out to seek out more food.

If its only small portions then the mantis was seen entering and exiting its burrow through out the day over half a dozen times but each bring back was a 'small' food item.

It makes sense for such a high energy utilizing animal to burn through food basically as often as they can acquire it, like a V10 car engine sucking down fuel like crazy!

This makes a lot of sense to me because my peacock is hungry all the time. I usually add a few shrimp pellets 2x a day in addition to the main meal every other day. The damsel eats the scraps that are tossed out and nothing gets wasted.

OP how often was it eating and what amount? Also what kind of filtration system?

[Cimmerians]

Wait so chances are there's a dead chromis rotting somewhere under that sand?

[Martini5788]

I would say probably not because your mantis was starving. But it's a possibility

[Martini5788]

You are going to have to give more information to let everyone help you. Tank size, filtration, lighting, water parameters, specifics as to feeding

[Kharn]

As martini said the best thing you can do is provide as many details possible many is NEVER too many!

Be as descriptive as you can, provide photos if and where you can.

1 image can speak 1000 words... It's why I am known to be so photographic a picture can describe what words simply cannot...

[Kharn]

And don't be afraid of admitting to a silly over looked simple mistake no one here will bash you for it and if they do then they do not deserve to be here, we learn more from our mistakes then our success...

[Kharn]

My entire journey to date with these animals has been built upon at FIRST failures...

I am never afraid to admitt that!

As Tyrion Lannister would say "Know your weakness and wear it like armor, be proud of yourself and your failures then no one may ever use it to harm you!"

[Calappidae]

Originally Posted by Kharn

And don't be afraid of admitting to a silly over looked simple mistake no one here will bash you for it and if they do then they do not deserve to be here, we learn more from our mistakes then our success...

^this

One thing about this hobby is you're never going to just jump into it, and have success from the start. You're guarenteed a trail and go through error.. after you've learned your lesson you'll know the mistake and (hopefully) never repeat it again.

I still cringe thinking about how my first O. scyllarus turned out and everybody bashed me like an outlaw, despite my lack of knowledge in general at the time.

[Cimmerians]

Thanks everyone, I'm planning on keeping mainly mantis shrimps (but never more than one at a time) for a long time but I've never dealt with the species before. In terms of tank info, I have nano cube filteration, LED lighting, 10 gal tank, shallow sand with tons of rocks ( but his beginning tank was tons of sand with little rocks), I've been feeding (or at least trying) him mostly shrimp kept frozen, but served to him thawed and on a stick. During his stay, the amnonia and nitrite levels were always 0 ppm but a nitrate level at a horrible 160ppm (or around that level) that never went down no matter how many water changes I did. Any contributing info that might be important to include is the fact that it's a mature tank, which use to be a reef before I moved it all to a 24gal tank to give the 10gal to my mantis. My shrimp seemed docile at first, but towards the end of his stay with me he was easily agitated, always punching his feeding stick or punching his rocks if I scooted the tank a bit. If any more info is needed please ask, I want to make sure I could provide my next mantis with the best possible conditions I could give it

[Cimmerians]

(this rock set up was more scattered when my mantis was in here, but now I'm hosting a chromis, banded coral shrimp, sand starfish, and a group of hermit crabs and snails to clean everything up)
sorry for the lighting, but here's what my shrimp looked like

[Cimmerians]

Not sure if it's needed or if anyone wants to see, but I also have a picture of my shrimp dead that I took in case it would help solve the mystery