In my shrimp tank I have noticed a few very tiny worms that even free swim in the water. They are very very small, probably not much fatter than a strand of hair and not very long either, when they swim they look like the waves on the sound wave measure machine thing, the name escapes me, I think it's an occimeter or something along those lines. I know it's almost impossible to have an aquarium without some sort of hitchhiker op but I don't know if these worms could be parasitic, are my shrimp at risk? My shrimp were not cheap and I've already had 2 of them die from the stress of shipping I presume. My water parameters are fine also.