Vitamin C must be added to koi feed primarily because koi cannot synthesize this essential nutrient on their own, and the vitamin C naturally present in conventional feed ingredients is highly susceptible to degradation. During the high-temperature pelleting process of feed production, most natural vitamin C is destroyed due to heat exposure. Even the small amount that remains post-processing continues to oxidize and break down during storage and transportation. Additionally, because koi live in water, water-soluble vitamin C is constantly lost to the surrounding water through dermal diffusion and excretion.
A deficiency in sufficient vitamin C can lead to weakened immunity in koi, increased susceptibility to bacterial diseases, slow wound healing, spinal deformities, and dull scale coloration. Therefore, to ensure healthy growth, disease resistance, and vibrant body color in koi, it is necessary to consistently supplement the feed with stabilized vitamin C through specialized methods, such as encapsulated vitamin C.
