Refrigerate Cod After Cooking [duplicate]

Yes, it's fine to refrigerate cooked fish. Many types of fish are excellent (better, even) served cold -- shrimp and salmon are good examples. If you can eat it cold, it's hard to see how reheating would pose any additional risk.

There are some other considerations, though. It's easy to overcook fish, which leaves it dry and less than tender, and that goes double if you're reheating. Use low heat (or low power in a microwave) and be careful not to cook too long. Some sauce will help keep the fish reheat, but avoid storing the fish in a strongly acidic sauce (like lemon juice) as acid will change the fish over time even in the fridge. And avoid reheating fishy things in the microwave at work if you value your relationship with your coworkers -- the smell often lingers.