In a message dated 5/19/98 9:47:28 AM EST, rgriffit@visa.com writes: << If one starts with a good group to choose from, and chooses the 'best of > the breed' for the qualities desired (i.e., look at the guppy, betta, > swordtail/platy) you will develop consistently good stock--the care must > be in ruthless selection and allowing, only allowing, the best of the > bloodlines to continue. >> Speaking of bettas, there is one species of "wild" betta that can only be bred in captivity a certain number of generations before all fry (note:ALL) come out females. They require regular infusions of wild stock to prevent this problem. IMHO, outbreeding, or crossing bloodlines between two different groups of breeder's stock will help to maintain the genetic diversity that was originally in the wild population from which the stock was extracted. Introductions of wild stock would do the same even better. Bob Dixon