Predatory capabilities of Caribbean Rock Mantis

[Tigershark22]

Howdy!
I have a Caribbean Rock Mantis, Wennerae (perhaps 2 if the larger one hasn’t killed the smaller one) that came with some live rock. The larger one is about 2” long currently. Super cool little guy, awesome to watch when I get to see him.

I am wondering what their capabilities are/will be once full grown since it’s one of the smaller species of mantis and I’d like to keep it in a mixed reef. To be more specific, how much larger of inverts or shrimp would they be comfortable attacking?

I didn’t think it would be capable of killing a peppermint shrimp that was larger than it but I haven’t seen the shrimp in over a week lol.
He was unsuccessful, however, of getting scarlet hermits.

 

[BristleWormHater]

@ISpeakForTheSeas

 

[littlefoxx]

@Stomatopods17

 

[Stomatopods17]

I'm honestly not sure if that's N. wennerae.

Would need a closer photo

 

[Tigershark22]

I'm honestly not sure if that's N. wennerae.

Would need a closer photo

Unfortunately those are the closest photos I’ve been able to get of one. I now suspect there to be at least 3 in the tank. Live rock came from the Florida Keys

 

[ISpeakForTheSeas]

I am wondering what their capabilities are/will be once full grown since it’s one of the smaller species of mantis and I’d like to keep it in a mixed reef. To be more specific, how much larger of inverts or shrimp would they be comfortable attacking?

I didn’t think it would be capable of killing a peppermint shrimp that was larger than it but I haven’t seen the shrimp in over a week lol.
He was unsuccessful, however, of getting scarlet hermits.

As a general rule, I would say a predator like a mantis may attack pretty much any critter it doesn't view as a serious threat to itself; so I would guess the other critter has to be big enough to feel intimidating to the mantis before it would be unlikely to try and kill it (provided the mantis has enough space to feel like it's not in immediate danger from the other critter).

N. wennerae (which I agree with Stomatopods17 that I can't tell if that's what you've got or not from the pic) are known to really only go after smaller critters:

n_wennerae

That said, shrimp in particular don't really have good defenses like hermits, snails, and crabs do (these all have tougher shells and crabs have snapping claws), so shrimp - especially when molting - would likely need to be like twice the size of the mantis to be safe.

 

[DaJMasta]

For reference, angry stomatopods will sometimes act aggressively to divers, so I would not consider any invert to be truly safe. If you've got a spearer type, larger snails are probably alright, and if you've got a smasher type, some "nano" fish may even be safe, but for smaller things (up to maybe 50% larger than the mantis) consider them at risk even if you keep it well fed.

They're capable, they're brave, and they're pretty smart.

 

[Stomatopods17]

Spearers can smash snails. I've been punched by a L. Maculata before. Smashers can spear, and spearers can smash, their functions are merely preferences in hunting rather than limitations. Spearers never 'mine' cavities or burrows so you won't hear or see them chipping away at things, while larger spearers will hit and crush shells.

General rule of thumb for anything coexisting is don't keep stuff thats slow, or expensive for obvious reasons.

Even if a mantis has no ill intentions, a fish/shrimp deciding to graze too close around it could get hit and that domino effect into infections/injuries etc. Only takes an accident once. Typically Damsels do well because they are fast, don't tend to graze in one spot (although I'd had them share burrows before), and stay a size where mantis aren't often in immediate interest to kill them. Spearers would be a different standard.

Peppermint shrimp would not last with a mantis, they're not fast swimmers (reactively), get badly injured in one hit, hide in caves/corners rather than upper water column, and mantis are highly opportunistic in the event it catches one around molting.

 

[Tigershark22]

As a general rule, I would say a predator like a mantis may attack pretty much any critter it doesn't view as a serious threat to itself; so I would guess the other critter has to be big enough to feel intimidating to the mantis before it would be unlikely to try and kill it (provided the mantis has enough space to feel like it's not in immediate danger from the other critter).

N. wennerae (which I agree with Stomatopods17 that I can't tell if that's what you've got or not from the pic) are known to really only go after smaller critters:

n_wennerae

That said, shrimp in particular don't really have good defenses like hermits, snails, and crabs do (these all have tougher shells and crabs have snapping claws), so shrimp - especially when molting - would likely need to be like twice the size of the mantis to be safe.

Spearers can smash snails. I've been punched by a L. Maculata before. Smashers can spear, and spearers can smash, their functions are merely preferences in hunting rather than limitations. Spearers never 'mine' cavities or burrows so you won't hear or see them chipping away at things, while larger spearers will hit and crush shells.

General rule of thumb for anything coexisting is don't keep stuff thats slow, or expensive for obvious reasons.

Even if a mantis has no ill intentions, a fish/shrimp deciding to graze too close around it could get hit and that domino effect into infections/injuries etc. Only takes an accident once. Typically Damsels do well because they are fast, don't tend to graze in one spot (although I'd had them share burrows before), and stay a size where mantis aren't often in immediate interest to kill them. Spearers would be a different standard.

Peppermint shrimp would not last with a mantis, they're not fast swimmers (reactively), get badly injured in one hit, hide in caves/corners rather than upper water column, and mantis are highly opportunistic in the event it catches one around molting.

Sorry for the late response here, busy week!

That is all incredibly fascinating info!

I know my pics aren’t good but N. Wennerae seemed to be the only species I could find in the Florida keys that resemble what these look like. Dark and light green striations down the body when under white light.
They are definitely smashers.
Are there perhaps other species in the keys that these could be?

The reason I posed the question initially is because I recently noticed blemishes on my tomini tang. They seemed minor and have since gone away.
But now my bicolor blenny has a couple serious gashes. This also started occurring after adding a spotted rabbitfish to the tank. Which is what I have assumed to be the cause due to his spines, though they always seem friendly whenever I am watching.

The mentioning of smashers potentially spearing has me wondering if a mantis could possibly be the culprit.
What do yall think the likelihood is of each scenario?
New tank mate and much larger/faster rabbitfish getting aggressive with its spines?
Or a 2-2.5in mantis smasher type being able to cut a blenny?

 

[ISpeakForTheSeas]

I know my pics aren’t good but N. Wennerae seemed to be the only species I could find in the Florida keys that resemble what these look like. Dark and light green striations down the body when under white light.

Not sure - the most important ID features for mantis shrimp are generally the meral spots and the antennal scales (the feather-looking things by the head); color generally isn't a great ID characteristic for stomatopods, as color can vary wildly for some species.

The reason I posed the question initially is because I recently noticed blemishes on my tomini tang. They seemed minor and have since gone away.
But now my bicolor blenny has a couple serious gashes. This also started occurring after adding a spotted rabbitfish to the tank. Which is what I have assumed to be the cause due to his spines, though they always seem friendly whenever I am watching.

The mentioning of smashers potentially spearing has me wondering if a mantis could possibly be the culprit.
What do yall think the likelihood is of each scenario?
New tank mate and much larger/faster rabbitfish getting aggressive with its spines?
Or a 2-2.5in mantis smasher type being able to cut a blenny?

My thought would be the rabbitfish, but do you have any pics of the injuries?

Some of the fish medic crew here could probably help us know if it looks like it might have come from the rabbitfish if you have some pics of them.

 

[Uncle99]

I found a mantis shrimp after 5 years.
It was 5”-6”. Used all dry rock so must have come in as a baby, then grew to size.

It stalked and killed 2 of my sand and rock dwellers.

Took out a royal gramma, beat the crap out of it first.

A week later, a dottyback, was found beaten up and stunned, then both gone.

By complete chance I was feeding the NPS at night and I seen him.

Not overly fast, but absolutely viscous. A killer.

Caught him. Now it’s out.

 

[Tigershark22]

Not sure - the most important ID features for mantis shrimp are generally the meral spots and the antennal scales (the feather-looking things by the head); color generally isn't a great ID characteristic for stomatopods, as color can vary wildly for some species.

My thought would be the rabbitfish, but do you have any pics of the injuries?

Some of the fish medic crew here could probably help us know if it looks like it might have come from the rabbitfish if you have some pics of them.

He’s not too shy, I will get some pics here shortly.

Thank you so much for the continued information.
As far as the meral spots on the mantis, I will have to see if I can get a good look.
The antennal scales that I’ve seen on one are rather colorful under white light, rainbow-ish or prismatic is how I would describe them

 

[Tigershark22]

I found a mantis shrimp after 5 years.
It was 5”-6”. Used all dry rock so must have come in as a baby, then grew to size.

It stalked and killed 2 of my sand and rock dwellers.

Took out a royal gramma, beat the crap out of it first.

A week later, a dottyback, was found beaten up and stunned, then both gone.

By complete chance I was feeding the NPS at night and I seen him.

Not overly fast, but absolutely viscous. A killer.

Caught him. Now it’s out.

Oh wow that’s a long time. What a stealthy creature

 

[Tigershark22]

@ISpeakForTheSeas @Stomatopods17
Howdy, are any of these photos good enough for an ID? I’ll admit they’re certainly not the color I thought they were. Don’t think I had it under pure white light until now

 

[Stomatopods17]

Leaning on N. oerstedii, but I need a better look at the meral spot on the inner part of the arms.

I can vaguely make out the meral has a white outline in the first image, but I can't tell if there's a dark spot in the middle for sure, looks like it but its blurry zoomed in.

If it has a purple spot, it's Oerstedii, if its clear white it's N. wennerae.

 

[Tigershark22]

Leaning on N. oerstedii, but I need a better look at the meral spot on the inner part of the arms.

I can vaguely make out the meral has a white outline in the first image, but I can't tell if there's a dark spot in the middle for sure, looks like it but its blurry zoomed in.

If it has a purple spot, it's Oerstedii, if its clear white it's N. wennerae.

I took those ss from this video.

Wasn’t quite sure what I needed to find but I think there’s some good angles for you here and I believe I even see the purple spot you mentioned for Oerstedii

 

[Stomatopods17]

Oerstedii

 

[Tigershark22]

Oerstedii

Awesome, thank you for your help. What size could I expect Oerstedii to get to at maturity?

 

[Stomatopods17]

Around 2 and a half inches in length

 

[Tigershark22]

Around 2 and a half inches in length

Thanks again for your time and expertise! I believe it’ll do just fine coexisting with fish. Happy to keep the cleanup crew stocked for it to hunt. Seems to love the clumsy cerith snails lol