Although they are ideal community tank residents with fishes of similar size and temperament, if you intend to breed guppies, it is best to house them in a species-only tank. You can house three pairs in a 10-gallon tank or five to six pairs in a 20-gallon tank. Available today in many color and fin varieties, all these guppies descended from the wild Poecilia reticulata.
The guppy is best housed in a 10- to 20-gallon long tank. This fish needs well-oxygenated water, but do not like much water motion, so a power filter is out. The old-fashioned inside box filter or a large sponge filter seem to work best. Decorate this fish’s tank with live bunch plants (potted) to offer the fish security as well as something to nibble on. Frequent partial water changes are a must because of the many feedings the fish should receive.
The guppy will consume a wide variety of meaty and plant foods. In particular, it relishes small live foods, flakes, freeze-dried Tubifex worms, algae, parboiled zucchini slices, plus any other small foods you can provide. The key is variety and frequent feeding.
The guppy is a live-bearer that is easily spawned in the aquarium without much preparation. However, if you want to breed good-quality guppies you will need to be selective. Choose a pair of guppies that have the color, finnage and size you like. Males are brighter in color, smaller and have a modified anal fin called a gonopodium.
Once this fish has spawned, separate out any males and raise these into healthy adults. Now you have your breeding stock. Choose a male and one or more females from the original batch and begin your selective breeding. In this way you will be able to properly control the genetics.