How to Keep Goldfish in Winter and the Right Water Temperature
📝 Summary
As temperatures drop in winter, lively goldfish grow sluggish, and safe overwintering is not easy for the small ones. Here are winter goldfish tips on feeding and keeping them warm.
1 Winter Feeding
Goldfish are cold-blooded, so low temperatures slow their metabolism, reduce activity and appetite, and halt growth. Cut back on feeding to avoid excess food spoiling the water.
While they still eat, feed once in the morning or once every 2 to 3 days, only as much as they finish in 2 to 3 minutes, and siphon leftovers right away. On cloudy, low-pressure days, oxygen drops and digestion uses more of it, risking oxygen shortage, so skip feeding.
To build energy for overwintering, feed daphnia to fatten them before winter and raise cold tolerance; if you use prepared food, mix in some fatty energy sources for extra nutrition.
2 Keeping Warm and Frost-Free
Keep the water above 10°C (50°F): below that, activity, appetite, and digestion fall; below 6°C (43°F) goldfish stop eating and barely move as metabolism fades; below 4°C (39°F) they go dormant, living on stored energy; below -4°C (25°F) they die. So when outdoor cold nears 0°C, move them indoors and keep the room at 2 to 10°C (36 to 50°F).
Winter means less eating and less waste, so don’t change water often and avoid adding water or cleaning much. Change about a quarter to a third of the water once a month, with a temperature gap under 2°C (3.6°F), and clear debris about weekly without touching the fish, to avoid wounds that lead to fungus or white spot disease.
Goldfish tolerate only 0 to 39°C (32 to 102°F). If winter water gets too cold, heat it or insulate the pond with straw or quilted mats so they don’t freeze.
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