What you are describing is pretty common. Some fish are just not interested in chasing food in the water column. Normal goldfish feeding is actually rooting around in the gravel at the bottom to look for food (this is called "booking"), and the catching of food in the water while we watch is actually a trained behavior ....
As long as the fish is getting the food, it is not really a problem if he wants to dig around for it. Poor eye-sight is also a possibility. My Moor (who is half blind like most moors) makes a pretense of getting food at feeding time, but he almost always miss. <The breeds with poor eyesight feed by smell.> He is surviving by eating all the leftovers in the gravel. He is growing & appears healthy, so I let him be. <Although I have to feed a bit extra so there are actually leftovers that reached the gravel before the other 8 hoover everything up!>
If you really want to watch you fish eat, you can try :
1. Always feed at the same spot, and at approx the same time so the fish knows it is supper time.
2. Put a flat rock or a small plate at the bottom & aim to have the pellets fall onto it. You can train the fish to always go to the dish for supper.
3. Hand feed your fish. Fun to do and make your fish more a pet. I would start with chopped (cooked) shrimp ... no goldfish can resist that! You can also feed veggies (peas, etc) & other "whole" food by hand. <Or even pellets.> Once the fish associate you with food, they will come begging every time you walk by. <My fish always come & nibble on my hand when I do maintenance.>
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