<Li> Ovoviviparity: Fertilization is internal; zygotes are retained in the female (or male) but without major trophic (feeding) interactions between zygote and parents (there may be minor interactions, such as maintenance of water and oxygen levels). The embryos depend upon their yolk for survival . </Li> <P> There are two types of viviparity among fish . </P> <Ul> <Li> Histotrophic ("tissue eating") viviparity: The zygotes develop in the female's oviducts, but she provides no direct nutrition . The embryos survive by eating her eggs or their unborn siblings . </Li> <Li> Hemotrophic ("blood eating") viviparity: The zygotes are retained within the female and are provided with nutrients by her, often through some form of placenta . </Li> </Ul> <Li> Histotrophic ("tissue eating") viviparity: The zygotes develop in the female's oviducts, but she provides no direct nutrition . The embryos survive by eating her eggs or their unborn siblings . </Li>

What is the gestation period of a fish