Fry reach about 3 cm in length 3 weeks after hatching. If left in the original pond, they will grow rather slowly because of crowded conditions and the lack of food. The summer fry, therefore, must be transferred to new ponds for rearing. This is because summer fry are small and cannot effectively escape enemy attack. They will suffer large mortality if transferred directly into large ponds. Additionally, the density of summer fry is normally about 20,000 to 50,000/ha, a density far too great for rearing fish to eatable size. 1 , 2