We've checked everything out in our ponds but what about our fish? The fish are swimming and coming to the top of the pond. Don't be in a hurry to feed them. The proper time to begin feeding the fish is when the water temperatures consistently reach at least 50 degrees and above.
On the few warmer days of spring they will come to the surface acting as if they want fed. The water should be stabilized around 50 degrees before you resume feeding. You will want to feed them an easily digestible food, such as a wheat-germ-based floating pellet to start with, since their digestive systems are still slow. Microbe-Lift makes a Fall/Spring Fish food that is wheat germ and easily digested. Feed the fish in the morning, feeding them lightly at first so that they will digest their food before the temperature lowers at night for a couple weeks. Once the water temperatures rise above 55 degrees, resume feeding them their normal high-protein food. Any good quality fish food with vitamins will work. Another good choice food for fish is duckweed or azolla. I always put some duckweed in a container in the shade so it grows and multiplies. That way I have it for a treat all summer long. I have heard also that frozen peas are good for fish. I haven't tried that but thinking about it now I will. Just to see if my fish like it.
You may want to add some flake food or balls of cooked oatmeal to your feeding regiment for the baby fish, once they start to appear in early spring.
You will want to make sure your pond water isn't high in ammonia or nitrites for your fish. You can buy test kits to check for this. I always check all the fish for any signs of infection or disease in the early spring so I can treat them before it gets worse. We sell a medicated floating fishfood that works well in treating fish. It is always easier to see the fish in the early spring, before the plants are in the pond.