Determining How Much to Feed Koi

Determining How Much to Feed Koi

  • 1
    Keep track of age. In order to determine the correct amount to feed your koi, you need to know the age, length, and weight of each fish in your pond, in addition to the water temperature. Find out how old your koi are when you purchase them and keep track of their age over the years. Keep a notebook or file with a description of each fish next to their stats.
  • 2
    Measure your koi’s length. As with age, keep detailed notes on the length of each fish in your pond. To do this, measure from the tip of their nose to the tip of their tail. Measurements should be taken in inches.
    • Domestic koi generally grow to 12 to 15 inches (30.5 to 38.1 cm) long.
    • Most koi reach 50 percent of their final adult length in 24 months, 95 percent at 10 years, and 99 percent at 14 years.
    • Update your notes at least twice a year to ensure your calculations are accurate.
  • 3
    Calculate your koi’s weight. Determining your koi’s weight is the next step in figuring out how much to feed your fish. Use the formula (weight) = (length x length x length) / (144). In this formula, weight is in ounces and length is in inches.
    • The most accurate way is to actually weigh your fish, although this isn’t always practical.
    • Charts can also help you determine its weight. Most give an estimate using the fish’s length and build. For example, typically, a 12-inch long koi weighs around 12 ounces.
  • 4
    Take the water temperature. The amount of food and frequency with which you feed your koi also depends on water temperature. A change in temperature impacts your koi’s eating habits. Higher temperatures quicken the koi’s metabolism, while lower temperatures slow it down.
    • When water is between 60 to 85 °F (15.6 to 29.4 °C), feed your koi two to four times per day. When the temperature lowers to 50 to 60 °F (10 to 16 °C), feed them once a day or every other day.
    • Monitor the temperature year round. If the temperature rises above 90 or below 50 °F (10 °C), it is best to stop feeding your koi as their metabolism will slow and they will not be able to properly digest their food.
      • Koi will still have access to food in those cases where the water temperature is too high or too low. They will be able to eat the algae on the pond liner or rocks.
  • 5
    Calculate the percentage of body weight as food per day. In order to determine how much food to feed your fish, you will also need to know what percentage of their body weight each fish must eat in food each day. Percentage of body weight as food per day is dependent upon the age of the fish, as well as the water temperature. Ask your local koi expert for a chart that lays out the percentage needed for each in relation to the other.
    • For example, a one-year-old fish living in 72 degree Fahrenheit water needs to eat two percent of its body weight in food each day. A four-year-old koi needs one percent. Take this percentage times the weight of the fish to determine how many grams of food it needs each day.
  • 6
    Calculate the amount of food for one fish. Once you have all your measurements and calculations, you’re ready to figure out the total amount you should feed your fish each day. To do so, use this formula: (length of fish) x (percentage of body weight as food per day) = amount to feed
    • For example, say you have a one-year-old fish that is five inches long and weighs 22 grams, living in 72 degree Fahrenheit water. According to your chart, it needs to eat two percent of its body weight per day. Your calculations would look like this: (5 in.) x (0.02 x 22 grams) = 0.44 grams per day
  • 7
    Calculate the amount of food for multiple fish. You’ll most likely have more than one fish in your pond, so you need to figure out the total amount of food you’ll need to feed all your fish each day. To get this number, add together the total grams needed for each fish.
    • For example, say you have a one-year-old koi and a four-year-old koi in your pond. The one-year-old koi is five inches long and weighs 22 grams. The four-year-old koi is ten inches long and weighs 200 grams. The water temperature is 72 °F (22.2 °C). Based on age, weight, and water temperature, your one-year-old should receive two percent of their body weight as food per day and the four-year-old should receive one percent.
      • Using the calculations from the previous step, the one-year-old needs 0.44 grams of food per day. The four-year-old needs 2 grams per day [(10 in.) x (0.01 x 200 grams) = 2 grams per day]. Add 0.44 and 2 together to get the total grams you need for both of your fish each day (2.44 grams).

Source:wikihow