My pond has gotten darker/murkier than normal and perhaps coincidence, perhaps not, my fish do not come up to the surface to eat like they have in years past. I'm using the same food I have used for years...any ideas?

They found a new source of food and there full.

Has the water quality changed much? Being out in the open, does it get enough shade, and does the pond take in runoff from the lawn? If you are relatively certain nothing has seriously compromised the water quality, then consider several buckets of a water change to help with the murkiness. Fish will not usually come up to feed if they are too warm, or of course- not hungry. What goldfish are especially good for ponds is to eat all the mosquito larvae. Its possible their preferred food source has improved. If you want to "test" that- try not feeding them for a week or so, then giving them your fish food. For most fish, not eating for several days is more "natural" for a fish, and their bodies can easily handle the sporadic feeding.

Maybe you should try a different food.