Most bony fish eggs are referred to as telolecithal which means that most of the egg cell cytoplasm is yolk.[1] The yolky end of the egg (the vegetal pole) remains homogenous while the other end (the animal pole) undergoes cell division.[2] Cleavage, or initial cell division, can only occur in a region called the blastodisc, a yolk free region located at the animal pole of the egg.