Mysis shrimp in my reactor?

[Cerberusfish]

So I saw these in my carbon reactor just now. At first I thought maybe they were Mysis shrimp, but upon googling pictures of live Mysis I question that a little. I also question how live Mysis would have gotten into the tank, and then gotten into the reactor to breed without being eaten.

 

[andrewey]

Looks like amphipods that were sucked into the reactor.

 

[peteyspizza]

+1 on the amphipods

 

[KJ]

Amphipod gammarid.