November is a critical month for pond owners across the United States. As fall foliage gives way to freezing temperatures, there is one non-negotiable step that determines the health and survival of your fish through winter: you must stop feeding them.
Ignoring this deadline is the single most common cause of fish illness and death during the cold season. Here is everything you need to know about the science behind the shutdown and how to protect your finned friends.
The 50 ∘ F Trigger: When to Put the Pellets Away
Your feeding schedule for fish like koi and goldfish is not dictated by the air temperature or the calendar—it is dictated by the water temperature.
Get a Thermometer: It’s Non-Negotiable
If you don’t have a pond thermometer, get one today! It’s the most important tool you own right now. The magic number to monitor is ().
Above : Continue feeding a high-quality staple or growth food.
to (The Transition): Switch immediately to a dedicated wheatgerm-based food. This food is lower in protein and easier to digest, preparing their bodies for the metabolic slowdown. Only feed once a day, and only what they consume in 5 minutes.
Below (The Deadline): STOP FEEDING ENTIRELY. This is your critical safety point.
The Science of Torpor: Why Food Becomes Toxic
Fish are poikilothermic (cold-blooded), meaning their internal body temperature is regulated by the surrounding water. When the water drops, their entire system slows down to conserve energy.
Digestive Shutdown
When the water temperature dips below , the beneficial bacteria and digestive enzymes in your fish’s gut become largely inactive.
What Happens to the Food? Any food consumed after this point sits in the digestive tract. It doesn’t get processed for nutrients; it simply rots.
The Result: This rotting food causes severe stress, inflammation, and introduces harmful bacteria directly into their system. This often leads to a fatal bacterial infection known as enteritis (gut inflammation).
Torpor is Their Survival Mode
Rest assured, your fish will not starve. They enter a state of torpor, a kind of deep, semi-dormant sleep. In this state:
Their metabolism drops to nearly zero.
They cease active swimming and rest on the deepest, warmest part of the pond floor.
They live entirely off the fat reserves they built up all summer.
Feeding them interferes with this crucial natural process and risks waking them up or introducing internal disease.
The Final Cleanup & Water Quality Check
While you’re putting away the fish food, perform these final steps to ensure a healthy environment while they sleep:
Remove All Leftovers: Use a fine-mesh net to scoop out any recent uneaten pellets. Don’t let them sink and decay!
Add a Cold-Water Boost: Even though the weather is cold, debris (leaves, sludge) is still decaying. A final, hearty dose of cold-water beneficial bacteria (like Nualgi Ponds) is vital. These specialized bacteria work in lower temperatures to break down organic sludge, which helps:
Keep the water cleaner over winter.
Reduce the buildup of toxic gases that get trapped under the ice.
Leaf Management: Ensure your pond is covered with a pond net or is regularly skimmed. Every single leaf that sinks will become sludge, increasing the potential for toxic gas buildup and taxing the water quality.
The rule of thumb for November pond care is simple: Less is more. Step back, let your fish rest, and enjoy the peace of knowing you’ve set them up for a successful spring.
