Because they are cold-blooded animals, the body temperature of fish and amphibians decreases with the water temperature in the garden pond, as does their agility. Fish and, to some extent, frogs gradually retreat to the bottom of the pond, “snuggle” into the mud at the bottom, and spend their winter dormancy there. Their metabolism and heartbeat decrease to minimal levels: For months at a time, the animals eat nothing and their hearts barely still beat.
Now is the time to reduce their feeding, to be readjusted to the full amount again later. Lower the amount of food in accordance with the amount the fish are taking in. Too much will encourage the growth of algae or off-gasing. Generally, it’s wise to feed pond fish an easily digestible food with a correspondingly higher nutrient yield. Because of the nutrient density, they’ll eat less of it and release less feces into the water, which will burden the filter less and result in fewer suspended particles and less thread algae in the pond water