Ghost shrimp and friends

[Atxpunx]

Not even a day after adding walmart boughten ghost shrimp I see flatworms and topepods in the tank. Could they be a nuisance ? Also is it confirmed the walmart ghost shrimp are brackish breeders or is it possible to have fry grow in freshwater.

 

[Revenantwing]

not sure about the worms, but the fry definitely can not grow in fresh water, must be brackish.