Do fish spend most of their time hunting for food or feeding

Some fishes  do. It all depends on the kind of fish, how rich in food their environment is, and how high in calories their diet is. For example, fish that eat algae have to eat a lot more of it than fish the same size that eat shrimp, because shrimp is much higher in nutrients than algae is.

Some fish can satisfy their nutritional needs with only a few minutes a day of feeding.
This kind of fish is likely to spend the rest of its time hiding somewhere.

Other fish have to spend nearly all the time hunting for food and nutrients , or (in some cases) filtering the water for tiny food items such as phytoplankton.