The proper transportation and handling of fish eggs and fry is a vital part of any fish production system. Careful planning is important. The first thing to decide is the type of container to be used to hold the fish. There are buckets and barrels of many sizes and designs, each with different characteristics. A second consideration is the density to which the fry should be packed in the container. It must be as dense as possible to save space and money, but not so dense as to kill the fish. The two most important factors in determining the maximum allowable density are water temperature and dissolved oxygen levels.