Fish development
The development of fishes is unique in some specific aspects from the developmentof other animals.
Cleavage
Cleavage, or initial cell division, of the fish zygote is meroblastic, meaning the early cell divisions are not complete. The yolky end of the egg (vegetal pole) lacks remains homogenous while the other end (animal pole) undergoes cell division.[1]
The fate of each of these first cells, called blastomeres, is determined by its location. This contrasts with the situation in some other animals, such as mammals, in which each blastomere can develop into any part of the organism.[1]
Neurulation
Neurulation, theformation of the central nervous system, is different in fishes than in most other chordates.
Sex determination
Many species of fishes are hermaphrodites.