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How can I tell if my fish are ready for a lighter diet?
ASKED BY: Steve of Wallingford, PA
ASKED BY: Steve of Wallingford, PA

How can I tell if my fish are ready for a lighter diet?

A:  When feeding your koi and pond fish, a "lighter diet" doesn't mean that your finned friends need to switch to low-cal, low-fat foods. Instead, it refers to an easy-to-digest wheat germ-based diet that's formulated for the fishes' slowed activity and metabolism during the transitional fall and spring months.

Wheat germ-based diets, such as The Pond Guy Spring & Fall Fish Food, are packed with vegetable protein, amino acids and digestive enzymes. These diets, which help them ease into and out of winter, are gentle on their digestive systems while keeping their constitutions strong to fight off disease.

How do you know when it's time to switch diets? Here are three clues:

  • Temperature: When your water temperature is 50 degrees Fahrenheit or higher, you should feed your active, hungry fish protein- and carbohydrate-balanced foods, like The Pond Guy Growth & Vibrance Fish Food. But when water temperatures dip to between 40 to 50 degrees, they require the lighter, wheat germ-based foods. Use your Pond Thermometer to keep an eye on the water temperature as the days and nights get cooler.

  • Fish Mobility: Are your koi and goldfish moving a bit more slowly than they normally do? That's another clue that it's time to switch to a lighter food. Fish will naturally begin to slow down their activity in cooler water as their bodies begin to prepare for their annual "hibernation."

  • Feeding Interest: As the fish slow their activity and require less food to fuel their metabolisms, they won't be as interested in the tasty morsels as they are in the summer. So if your koi and goldfish seem to have turned into picky eaters, that's your third clue that it's time to switch to a lighter diet.

When water temperatures fall to below 40 degrees, that's when it's time to stop feeding your fish altogether. Don't worry: They won't starve! Their bodies, which need very few nutrients to sustain them during the cold months, have plenty of fat stored—but you can bet they'll be ready for a nice, big meal when spring arrives.