ABSTRACT
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. Before the planting of summer fry of black roach, a large amount of Daphnia should be cultured through fertilization. The advantage of selecting strong fish for transferring is obvious; weaker fish cannot stand the strain of shipping, and they are less able to withstand adverse conditions in a new pond. In mixed rearing, it is important to have the proper proportion among species, or the growth of some fish will be affected. In extreme cases, an entire species may be eliminated. Even though the density of summer seeds is usually smaller than that of fry, the young fish require a lot of food for rapid growth.
