A winter pond largely looks after itself if two things keep working while you are away: water keeps moving through the filter, and gases can still escape at the surface. Feeding, by contrast, shrinks to almost nothing in cold water, because goldfish digest slowly in winter and uneaten food fouls the water that the fish must then live in for weeks.
Filtration That Keeps Running
Leave the pump and filter running for the whole trip rather than switching the system off to rest it. In a stocked pond the filter community and the gentle circulation matter in winter too, and a system left off can leave water still, cold in the wrong places, and harder to restart cleanly on your return. Before you leave, check the pump is drawing steadily, clear leaves and sludge away from the intake, and rinse filter media only in a bucket of pond water if it genuinely needs it, several days before departure rather than on the morning you go. Keep the return flow gentle: winter goldfish rest in the deeper, stiller layer, so the outlet should keep water moving without churning the whole pond or blasting the bottom where the fish are sitting.
The Ice Hole and Gas Exchange
When ice forms, it seals the surface, and a sealed pond traps the gases that decaying matter and the fish themselves produce. One clear hole in the ice, kept open for the whole frozen spell, is what allows that exchange to continue. Ask your checker to confirm on each visit that the hole is still open. If it has frozen over, the hole should be reopened by resting a pan of warm water on the ice until it melts through, or by pouring warm water gently at the edge of the hole. Ice should never be smashed or hammered, because the shock travels through the water to fish that are already conserving energy in the cold. A floating ball or a small pond heater that holds one patch open can do the same job, provided it is in place and working before you leave.
Feeding Only When the Fish Ask for It
Use the fish and the weather together as the rule. In a cold spell, when goldfish sit low and still in the deeper water, feed nothing at all, however long that spell lasts. On a mild day, typically when the water is around 10°C (50°F) or warmer and the fish have risen, are swimming, and are visibly looking at the surface, a small amount of food is reasonable, and only as much as the fish clear within a few minutes. If the fish drift away and leave food behind, feeding stops at that visit and nothing more goes in until the fish are active again. Write this rule down for your checker in plain words, because a kind helper's instinct is to feed daily, and daily feeding is precisely what a winter pond does not need.
The Checker's Visit, in Order
On each visit the checker should look at the hole in the ice first, then confirm water is still moving at the filter return, then watch the fish for a minute before deciding anything about food. Leaves sitting on ice or netting should be lifted off so they do not rot into the water during a thaw. If the power has failed, the water has gone still, or fish are gasping at the hole, the checker should ring you the same day rather than waiting for your return, since gasping at the surface is a pond asking for help with its air, not with food. On your return, restart nothing dramatically: confirm the filter is running, clear debris gradually, and resume feeding only as the fish's own activity builds. For the next trip, KinsLe lets you revise the Care Pass with the dates the pond iced over, so a future checker works from your pond's own winter history.