Help with critter ID please - baby shrimp?

[phippsj]

I have about a dozen or so of these things in my fuge... not sure what they are... perhaps baby shrimp or some other bug? They are about 1/8" big right now, very hard to get a photo of. The white you see in the picture is 3/4" gratting, so you can tell I had the camera as close up as it would go. They really seem to like hanging out in the mangrove roots.

Any help with the ID is appreciated