pod or baby mantis?

[Icefire]

I spotted at least 3, in sump and display.

You can see some big white "club"

 

[papagimp]

Grammarus Shrimp, larger amphipod, can reach up to 1.5"-2" but most are 1/4" or less. Very good pod for your tank, breed readily and prosper, feeds on left over food bits, decaying plant matter, stuff like that. Will support eating habits of dragonettes, wrasses, and other pod eaters. The nauplii are really tiny and also help to feed filter feeders and/or corals. This is a good critter to have and very common hitchiker.

 

[Icefire]

might be, aren't gamarus shrimp freshwater?