Ideal Growth Rate
Young grass carp grow quickly if allowed to feed in an environment with an adequate source of desired plants. In some cases, grass carp can grow at a rate of 2 pounds per month. This rapid growth rate requires a combination of warm water, adequate oxygen as well as plant vegetation. This growth rate decreases as the fish ages.
Sterilized grass carp live as long as 10 years under ideal circumstances. Female fish can reach 40 pounds as a mature weight, with male fishes slightly smaller. The non-sterilized grass carp can live 20 years or longer.
The consumption rate increases as the fish grows with fish less than 6 inches in size eating about 8 percent of their body weight every day. By time the fish is about 2 pounds in size, it consumes its weight in grass every day. Peak consumption occurs in fish between the weight of 2 pounds and 10 pounds where consumption drops off to about 25 percent of the fish's body weight. The fastest growth occurs during the periods the fish is consuming the most feed.
Temperature and Growth
Grass carp tolerate cooler temperatures but consume less food and grow slower. Water temperatures below 50 degrees result in inconsistent feeding. The highest rate of feed consumption occurs when water temperatures are between 70 and 86 degrees. The warm temperatures not only result in greater grass consumption but in higher growth rates.