The Rhino shrimp are normally seen in FW
. Apparently like several other varieties, of creatures, like Amano shrimp and Nerite snails, they breed in SW
. With shrimp young having a larval planktonic phase.
Edit: The pics you have do not look quite the same, though, there are many, many shrimp which live in similar environments and look similar, thinking of Ghost shrimp as one, or grass shrimp and looking similar, are hundreds of varieties world wide (I read that, lol