If you want to breed good guppies, you need one decently sized tank, or two slightly smaller tanks, or four small tanks. If you go with one tank(volume of 40 gallons or more), divide into three tanks. One fry tank, one birthing tank, and one adult tank. Preferably you would separate the sexes of fry with a fourth tank. If you go with two tanks, divide each tank into two, as described above. If you get four small tanks, just use them as described above. Carefully select a good strain of guppies. The strain should be known for good color, pattern(if there is one), large bodies, and large finnage. They should also breed true. Find a breeder of your strain and buy a trio. Place the trio in your breeding tank. When the females are ready to drop, transfer to the breeding tank. Once they drop, remove the female and let the fry grow a little so they aren't ripped apart by older fry(personal experience here). Then sex them and place in either the single growout tank or the tank they should be in according to their sex. Note that some 'females' will turn male. Once the fry are old enough not to be eaten, get rid of most except for a select few and place those one or two in the breeding tank.
