Yes feeding them once a day is enough. I usually go a few days in between feeding on occasion. Pretty much feed mine whenever the mood hits me, which is sometimes once a day other times every few days or so. There are quite a few on here that don’t feed there fish much at all, I did this a few summers back and my fish did fine fending for themselves most of the time that year.
Feed the fish what they can consume in a few minutes or so. I usually just throw a bunch of food in there, see how they do eating then give them some more if their behavior indicates they are still hungry. For a smaller pond(more like an outdoor fish tank size)I wouldn’t leave any uneaten food in the pond, to contribute to the fouling of the water.
I let the fish behavior dictate when I stop feeding them more so than a set water temp. If they are acting hungry then I feed them, granted when it’s cold they don’t eat as much food. So I only toss a little bit in to see if they have some interest if not then no more food for them.
I will add that my pond is much larger than yours and a well established pond with a lot of life in the pond for the fish and other inhabitants to feed on. I also, use a bog and plants in the pond as a natural filter to maintain water quality.
