The guts, heads, skin or any other part of the fish that people do not eat can be turned into organic fertiliser by fermenting or composting it. Fish waste is rich in nitrogen, phosphorus, calcium and vitamins. By applying fish fertiliser, we can increase the good microbes in the soil, so the soil gets healthier and nutrients become more readily available to plants. This makes the crops grow stronger roots and leaves, to better resist pests and diseases, and yield more. Fish fertiliser also improves crop quality.