Sure they're yamato? Any other shrimp in there? I've a bunch of baby yamato shrimp floating around in saltwater and they seem to be at home.. I don't really think they'd survive freshwater. BUT, yamato breeds in the hundreds at a time.. maybe one or two is super shrimp and survive. And how your baby yamato look like? Mine look like mosquito larvae at first.. now look more like shrimp...