Amphipod or baby mantis?

[Fungus]

After adding certain rocks from the LFS I began noticing amphipods. They multiplied rather quickly and look like the profile photo below with the black background.

There's a larger (9 mm) creature that looks similar to the others, except its antennae are longer (about 6mm) and I can see two large forelegs that resemble the characteristic mantis legs. Maybe I'm paranoid, but I just wanted to make sure with y'all. I suppose the long chelipeds are not unique to mantis shrimp...

I apologize for the poor images. It's hard to get a good photo of it because it's small. But here are my best attempts of this mysterious shadowy figure. The coral frag next to it is about 3cm wide.

 

[Jaybird]

I'm looking but I can't see anything in the shots. If it's that active during the daylight times for the lights I would wonder about it being a typical amphipod. All mine disappear during the day and you only see them at night.

You could try catching it with a net if it always hangs in the same place.

 

[Fungus]

Thanks for the reply. I annotated the images for clarity. It's funny how the eye sees things that I know are there

 

[mr_X]

amphipods, and perhaps an isopod. neither will cause you any grief.