Mantis tankmate?


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I have a 6 or 7 inch peacock in her own tank. In my other tank I have an 18inch diameter yellow brittle star that keeps eating all of my fish. I've had it since it was tiny, so I don't want to get rid of it. Would they be compatible? I need to find a solution.


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If it was eating fish do you think it might try and go for the mantis? I would think the mantis would put up a good fight if it tried.

DoubleM 10

Active member
i have my peacock that is about 4-4.5 in with an urchin, 3 damsels, feather duster, torch coral, xenia coral, sally lightfoot crab, red leg hairy hermit, and im 95% sure that he just hasent had the opportunity to get them by surprise.

i have seen the urchin with some broken spins so im sure thats how he is making it passed. the damsels are to fast. he would have to catch them by surprise. hermit has a good shell. the sally has been hiding inbetween the rocks. feather duster and the 2 corals dont phase him.

i doubt my mantis would go for a sea star. only because most of the time the star would be in the rocks pretty tightly. IMO


Invert Sexy Time!
Wow. I would think the sally lightfoot would be lunch in a hurry. At least with the way my mantis takes out fiddlers.

I have a fromia star in my Ternatensis tank with no issues. He ignores it.


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So I bought and setup a bigger tank for the two. I'm cycling it now. When it's time to move them, any ideas about which I should add first?

King Nikon

New member
I always hear conflicting answers, but I'll tell you what I did for both my peacocks.

My first one I put the peacock + chromis in at the same time, I later added false percula clownfish and a lawnmower blenny. I never had any casualties.

My second one I added a chromis, then a cardinal fish, then a month or two later a peacock when I finally got one. I don't have any casualties as of now (except for my chromis disappearing one night, but this was before the peacock was introduced)


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My N. Wennerae mantis did stay away from my starfish until it started to get real hungry when my CUC got low. Now the starfish has about 1/3 of one arm missing and I do see the mantis wack at it every so often, but typically just telling the starfish to move.

I have lost a Cardinal and Angel recently. My other Cardinal has a busted lip which looks like the mantis wacked it. Once I get my cleanup crew back to the correct level I don't think she will go after fish anymore, however she might just have the taste for fish now.

If the question is "Will a mantis eat fish?" or "Will a mantis eat a starfish?" then the answer is YES. If the question is "Will my mantis eat my fish?" or "Will my mantis eat my starfish?" then the answer is maybe. It depends on how hungry they are and how easy their prey is to kill. The hungrier they are the more apt they are to kill prey that are hard to kill.

King Nikon

New member
Oh yeah, I forgot to mention, when I got the Cardinal I also got a longspine urchin at the same time.

They are both still in the tank with my peacock.


New member
Here are the inhabitants I have with my Peacock Mantis.

-3 Blue Legged Hermits
-2 Turbo Snails
-1 Serpent Star

The only casualties I have in the tank are the gulf shrimp and small clams I feed him. He leaves everything else alone. He could really care less about the serpent star. That makes 2 of us....

Johnny Tang

New member
I have a 5" female peacock in a 20 long with:
star polyps
coco worm
about 30 dwarf ceriths
20 blue leg hermits
2 fiddler crabs (been in there for about 2 weeks now)
1 small gulf shrimp (for a week)

This female is really not as aggressive as other peacocks I have had in the past. My first male (~7") was super aggressive. He used any hard coral for a door or just turned them upside down and buried them. My first female was good. She didn't bother any corals too much. I would occasionally find a new frag for a door but eventually she got the idea no to do that anymore.

I really think it has to do with how big of a tank and how often you feed them. I'm sure you can get away with a lot of stuff but just don't get too attached in case something goes disappearing.


New member
So my tank finished cycling, and the mantis is in there now. I don't think I'm going to put her and the brittle star together. I just don't want to risk anything. The mantis seems to be liking her new home though.


New member
I just actually started adding starfish to my 55g and they all seem to get along pretty well. My peacocok, just molted and everything seems fine.

5 different species of Starfish total.
Inculding a very large brown and white brittle star. Probably 2ft from tip to tip. Main mouth disk is about 2" in diamter.


New member
Thank you for all the replies everyone.

We should probably let this thread die. We don't want noidster to get his panties in a bunch any more than they already are.