what is the shrimp???

[playtime]

I took a quick look in my tank and noticed this littl shrimp. I mean shrimp!!! it is clear ane about this big(---) from tail to head. when it saw me it hid under a snail shell. right now it looks like a cleaner shrimp but it is clear, could that be it? What do baby cleaner shrimp look like? If it isn't that, could it be bad for my tank. It had to come from somewhere, My tank has been set up for6 months now so it couldn't have come on live Rock could it. The last rock I added was about 1 month ago but they didn't have any hiding places, no crevices. Pleas help ID this guy?
Playtime

 

[b_ball12_99]

Sounds like an amphipode to me. They are a larger version of a copepode.

 

[playtime]

I did a quick search on amphipode and it seems I have had the same question with diffrent descriptions but get the same answer so that has to be what they are. I guess it really doesn't matter, I thought my cleaner shrimps may have multiplied and I was a little excited. Oh well, If anyone else has any other suggestions feel free. Thanks again.
Playtime