Answer:
The freshwater is hypotonic to the fish
Step-by-step explanation:
A marine fish is adapted to living in water that is salty.
The fish will not survive because the freshwater would be hypotonic to the body of the fish and as such, excess water would enter its body which will lead to its death. The cells that make up the body of the fish will take-in excess water and lyse, leading to the death of the fish itself.