Might as well throw in my two cents... Like dieselplower, I also feed when the fish appear hungry. We have weird weather patterns here -- we just had over a week of temps near 0F, and this week we are in the 50's and 60's. However there are plenty of times when the fish are active, but not actually feeding. Over the years, I've noticed that my fish really only seem to feed when the water temp gets well into the 40's. You certainly don't want a lot of extra food floating in the water and causing more problems, so I try to keep the feeding to a minimum, but I don't think my fish have ever gone more than a couple months without eating.
On the other hand, I also agree there is never a shortage of microbial foods for the fish to snack on. I had my waterfall cleaned up pretty nice recently, then we got this cold spell and the waterfall was completely encased in ice for over a week... When I broke the ice free, the bricks were completely coated in dark green algae again! The stuff doesn't care about the cold, but apparently being sheltered was enough for it to take off growing again. I also have more plant roots in the water than the fish can eat, so they certainly won't go hungry... but I still like to give them a little processed food through the Winter just to vary their diet.
On the other hand, I also agree there is never a shortage of microbial foods for the fish to snack on. I had my waterfall cleaned up pretty nice recently, then we got this cold spell and the waterfall was completely encased in ice for over a week... When I broke the ice free, the bricks were completely coated in dark green algae again! The stuff doesn't care about the cold, but apparently being sheltered was enough for it to take off growing again. I also have more plant roots in the water than the fish can eat, so they certainly won't go hungry... but I still like to give them a little processed food through the Winter just to vary their diet.