Once you have purchased your trio of guppies (1 male, 2 females) and they are have been safely housed in their tank (5 1/2 gal. Or 10 gal. tank), the only thing you can do is wait until the females are ready to have their young. When the female looks like she is pregnant you can place her in her own tank (it takes approximately 28 days from the day they're bred). This tank should have some form of protection for the newborn babies to hide from the mother as she may decide to eat the young. The first tank with the female will be known as "line A" and the second tank with the female shall be known as "line B". Both females have now had their batch of young. After "line A" young have matured and you have picked out the best male and female, breed them to each other, the young from this mating shall be know as the "A1" generation or the first generation for the "A" line. When the young from "A1" have matured the same procedure is started over but now you have "A2" (the second generation). This will continue for 4 or 5 generations and then the best male from the "A" line will be crossed to the best 2 females of the "B" line. The same routine happens for the "B" line as well, best male from the "B" line will be crossed to the best 2 females of the "A" line. Then the whole line breeding chart can be followed again and again. This is a very good way to maintain and improve a guppy strain. Breeders have had lines of guppies for over 10 years. At some point in time you may realize that your fish are not improving and even getting smaller or losing color, etc., it is at this time that you may consider outcrossing to another related line to improve your line, make sure that you cross to a pure line of guppies. Crossing to a well established line will ensure that you don't get young consisting of every color under the sun. The guppies you get from two established lines can some what be predictable as to what they will look like, and more than likely, not be a waste a time.