Koi do not digest the way a warm-blooded pet does. Their gut speed is set by the water around them, so the same handful of pellets that is a good meal in warm water can sit undigested and fouling in cold water. That is why spring and winter feeding are really one skill read at two ends of the year: feed by the thermometer, restart gently, taper honestly, and stop when the water says stop.
Spring: Restart Small and Digestible
When the water begins to warm and the koi come up looking for food, restart with small, digestible meals, offered once a day or less at first. Early spring water still swings cold overnight, and a fish that feeds eagerly on a mild afternoon may digest slowly by morning, so small and light beats generous every time in this stage. Watch the fish rather than the scoop. Meals they rise for and finish within a few minutes can grow, in size and in frequency, as the water temperature and their appetite rise together; meals they mouth and leave should shrink back down. Remove uneaten food promptly, because leftovers in a warming pond feed algae and bacteria instead.
Resist the urge to make up for winter in the first warm week. The filter and its bacteria wake up on the same slow schedule as the fish, and heavy feeding before the filter is working loads the water with waste at the very moment the koi are at their weakest after the cold months.
Autumn Taper and the Winter Stop
As the water cools again in autumn, taper in the mirror image of spring: smaller amounts, lighter food, longer gaps between meals as their interest fades. Then stop feeding once the water holds below about 50 °F (10 °C). Holds is the word that matters — a single cold night that dips under that line, followed by warmer days, is not the stop signal; water that sits at that level day after day is. Once feeding has stopped, leave it stopped through properly cold winter water, even on a mild afternoon when the fish drift up. A koi resting in deep water is not starving; its whole system has slowed to match the cold, and food offered in that state does more harm in its gut and in the water than good.
Depth is part of the winter plan. In a pond about three feet or deeper, koi settle into the steadier water near the bottom, below the coldest layer and any ice, and rest there until spring. Keep a small area of surface from freezing solid where your climate freezes ponds, so gases can escape, and otherwise leave the fish in peace.
One Seasonal Plan for Every Feeder
Pond fish get overfed by households, rarely by individuals: one person feeds at breakfast, another adds a handful at noon, and a third feeds again because the fish looked hungry, which koi always do. Agree the seasonal duties before spring arrives. Nina feeds on weekdays and Chris feeds on weekends, both working from the same posted amounts for the current stage — spring restart, full season, autumn taper, or stopped — and both reading the same pond thermometer before deciding that a stage has changed. Whoever feeds notes the amount and the water temperature, so the next feeder sees what the fish already had that day and what the water is actually doing. That stage table lives in the Family Sharing notes for the pond, where the whole household reads the same amounts.
Share the thermometer rule through the Family Sharing page on KinsLe before spring, and every feeder stops or starts on the same reading.