Would like to add to the discussion here that INTRACYTOPLASMIC SPERM INJECTION(injecting egg with sperm) in teleost fishes is not the best method for making hybrids or for reproduction of fish period. This method is only possible when the sperm is injected directly into the micropyle(an opening for entry by sperm on the cell wall of the egg). When this is accomplished the fertilization rate is less than 30%, and survival rate of those fertilized eggs is only about 15%, of that 15% only 2% will mature normally and develop past the embryonic stage. This method therefore is almost never used when hybridizing teleost fish species. It is most useful in mammalian species, and was first used on hamsters before being used on chimps and eventually refined into what is used in humans as invitro fertilization. I hope this is helpful to all those that always wondered how hybrids are produced. The method for making hybrids is as simple as those used by fish farmers. The eggs and sperm are stripped and combined in a controlled environment that is most conducive to fertilization. The rate of fertilization varies depending on which two species you are combining. As you can imagine the closer related the two species are the higher the rate of fertilization will be.
