chaeto algae hitch hikers???

Ok so I bought a chaeto algae today and found four different types of hitch hikers in it. First one was a snail, it was really really small. Next one was a Asterina starfish thats pretty small too. Next one was a brittle star I really like it. The fourth one concerns me. I dont know exactly what they are but they look like clear shrimp. They range from the size of fleas to the size of rice crispys. They keep curling up and springing through the water like my freshwater lobster once did.They seem to have antenna. They also seem to all be on their side. There are about 50 of them living inside the chaeto algae and is stopping me from actually put the algae in!
I looked around online and it might be some sort of pod? Leaning more towards amphipod but could be isopod copepod?
My camera isnt good enough to take a picture of them sorry.
Any help would be appreciated
Thanks!

 

grats on those finds. recently i got a chaeto bull of aiptasia.... it sucked

 

they sure sound like amphipods

 

Sounds like you have some beneficial pods and you are good to drop this algae into your refugium. The little Asterina starfish will multiply quickly – good for you.