Changes

There is great diversity in the reproductive systems of fish.  Some produce eggs and sperm for external fertilization, while others copulate with the discharge of either fertilized eggs or young fish. There are several categories which can be used to divide fish into reproductively similar groups as follows:

There is great diversity in the reproductive systems of fish.  Some produce eggs and sperm for external fertilization, while others copulate with the discharge of either fertilized eggs or young fish. There are several categories which can be used to divide fish into reproductively similar groups as follows:

== Dioecism, Parthenogenesis & Hermaphrodism ==

= Dioecism, Parthenogenesis & Hermaphrodism =

=== Dioecism ===

== Dioecism ==

* The majority of fish are '''Dioecious''' (a species that possesses both males and females in separate bodies).

* The majority of fish are '''Dioecious''' (a species that possesses both males and females in separate bodies).

=== Parthenogenesis ===

== Parthenogenesis ==

* An asexual form of reproduction found in females where growth and development of embryos occurs without fertilization by males.  

* An asexual form of reproduction found in females where growth and development of embryos occurs without fertilization by males.  

* Occurs in very few fish species.

* Occurs in very few fish species.

=== Hermaphrodism ===

== Hermaphrodism ==

Hermaphroditic species can be either simultaneously hermaphroditic or sequentially hermaphroditic.  

Hermaphroditic species can be either simultaneously hermaphroditic or sequentially hermaphroditic.  

==== Simultaneously Hermaphroditic Species ====

=== Simultaneously Hermaphroditic Species ===

* Each individual is both male and female at the same time

* Each individual is both male and female at the same time

* Ripening of the gonads may be sequential to prevent unnecessary self fertilization.

* Ripening of the gonads may be sequential to prevent unnecessary self fertilization.

==== Sequentially Hermaphroditic Species ====

=== Sequentially Hermaphroditic Species ===

* Any given individual is only one gender at a time, but can change gender when necessary.  

* Any given individual is only one gender at a time, but can change gender when necessary.