Zeigler Koi Grower Zeigler Koi Grower is a high performance diet designed to meet the demanding needs of growing fish during earlier stages of development. This diet contains spirulina and other natural marine ingredients to enhance the vibrant colors of your fish. Stable vitamin C and brewers yeast are included to help improve immune function and promote healthy tissue development. Higher levels of marine protein sources are incorporated to maximize palatability, digestibility and growth. Koi Grower is also supplemented with Vpak, an all natural additive, to help increase resistance to diseases. Available in 20 oz. and 5 lb. packages.