What is this thing?

fishfreak91 · Feb 20, 2021

Does anyone know what this is? It showed up out of nowhere and has been eating snails. I don’t know if it’s killing the snails or just feeding on the dead ones. Is it good or bad for the aquarium?

MrNYCeGuy · Feb 20, 2021

That my friend looks like a mantis shrimp. They will come in liverock from time to time. They will eat just about everything in the tank, fish, snails, crabs so you’ll want to remove him. You can purchase mantis shrimp traps to take him out of your tank. They are cool if you keep him in his own tank but don’t leave him in your main display tank.

SakuraSky · Feb 20, 2021

That's a mantis shrimp for sure!!!! Cool!

JGT · Feb 20, 2021

Bad. Get it out ASAP.

SakuraSky · Feb 20, 2021

SakuraSky said:
That's a mantis shrimp for sure!!!! Cool!

And I mean cool as in....in its own tank as a single specimen LOL

Gtinnel · Feb 20, 2021

I agree mantis shrimp. Once removed from your display it should be fine in your sump (if you have one), or you should try to sell it or give it away instead of killing it. I just saw one at a pet store for sale today.

mdb_talon · Feb 20, 2021

It eats everything up to small children.

vetteguy53081 · Feb 20, 2021

There are many that desires such hitchhiker slash nightmare. You will hear from it, some clicking sounds and yes it east all shelled creature and in the ocean mantis shrimp eat fish, crabs, and worms. They are nocturnal so they mostly hunt during the night, but if some crab or fish comes nearby their burrows, they will not let them go and knock them down with just a single punch. The striking Powar of this small shrimp is absolutely large.

ScottR · Feb 20, 2021

It will be tough to catch. Will need to remove all rock. But you can sell this guy. Many people out there really want one. I don’t what type yours is but it is green which is of the nicer type. So don’t throw him out. Give him a good home and maybe make a few $$$.

mindme · Feb 20, 2021

I bought live rock 1 time in my life. It was literally a piece of rock about the size of a softball. I was only using it to seed a reef tank about 10 years ago.

It had a mantis shrimp in it. I tried to catch it, but ended up killing it. He would not come out of the hole for anything. It was too bad because he was a bright purple, but it wasn't one of the ones with a hammer, it had the swords.

Good luck.

ca1ore · Feb 20, 2021

Depends on how large it is. Small ones aren’t that much of a problem. Have had them many times. The big ones are more of a problem. Bristleworm trap will usually get them.

vetteguy53081 · Feb 20, 2021

I had an easy time catching one using a fish trap with a snail inside of it. Clam on a shell may also work

Dom · Feb 20, 2021

If you can catch it, I'll take it off of your hands. Depending on where in the USA you are located.

fishfreak91 · Feb 20, 2021

MrNYCeGuy said:
That my friend looks like a mantis shrimp. They will come in liverock from time to time. They will eat just about everything in the tank, fish, snails, crabs so you’ll want to remove him. You can purchase mantis shrimp traps to take him out of your tank. They are cool if you keep him in his own tank but don’t leave him in your main display tank.

Dom said:

If you can catch it, I'll take it off of your hands. Depending on where in the USA you are located.

Click to expand...

MrNYCeGuy said:

That my friend looks like a mantis shrimp. They will come in liverock from time to time. They will eat just about everything in the tank, fish, snails, crabs so you’ll want to remove him. You can purchase mantis shrimp traps to take him out of your tank. They are cool if you keep him in his own tank but don’t leave him in your main display tank.

Click to expand...

Thank you for the info

fishfreak91 · Feb 20, 2021

Where can I find a trap for him?

Sarcazian · Feb 20, 2021

mdb_talon said:
It eats everything up to small children.

LOL

I couldn't help but laugh and this is coming from someone that has never actually had one in a tank as a hitch kicker. I did pick one up at a local LFS years back and placed him (smasher) in a small 15g acrylic tank tapped into my DT with corals/LR. He was cool, but maybe I gave him too much LR since I rarely saw him.

That looks like a smasher and he shouldn't touch your fish unless super desperate. But, inverts are totally on the chopping block.