How Small do Mantis Shrimp start out?

[crypt keeper]

I have a very very small Mantis looking creature in my fowlr digging out a small cave forhimself on a rock piece right against my glass. THis guy looks just like a mantis IMO but is very small. Im talking not much bigger than some of the odd looking pod all over my glass. He is big enough that he can move grains of sand one by one and is doing so at a fast rate. He almost looks as though he is psinning around in a complete circle end over end while moving the sand.
Its too small for my amazing camera to photo.
I do have some pics of my huge Peppermint shrimp. They are coming up on a year old. As are my clown fish.

 

[cranberry]

I've had 2 small guys.

Another one.
The yellow arrow is him. The red if a piece of mysis for size comparison.

 

[crypt keeper]

It just may be one. He is smaller than a piece of mysis. My trigger will make quick work of him that small. I will let him be for now.