It will not be able to survive for long because:-
- Water will enter the body by endosmosis
- As marine fishes drink lots of water, so excess water enters.
- It does not have salt absorbing mechanism as of freshwater fishes.
So, these fishes will die because of problem in osmolarity maintenance But due to hormonal mechanisms, migratory fishes are exceptions as they withstand the changes
eg:- Hilsa, salmon