A Few Things You Should Know About A Pregnant Guppy
Put a male guppy in with a female guppy and chances are good that within a very few days you will have a pregnant guppy. A female guppy can become pregnant about once a month. Given the fact that the average gestation period runs is 28 days, sometimes a bit longer, and sometimes not more than 20 days, the female is quite apt to spend most of her life being pregnant. Put a male guppy in with several females and within a few months you could have hundreds of guppies and a definite need for more space to keep them in.
The fact that a guppy is often a pregnant guppy is one of the reasons why, of all of the freshwater aquarium fish species, it is one of the most popular. Because of the rapid fire rate of reproduction, it is easy to breed guppies to get just the color and quality you are seeking. If your goal is to raise show guppies, the best way to get started is to buy a pair from a reputable guppy breeder. Many choose to purchase a male guppy along with a female guppy that is already pregnant, and due to drop (give live birth) within a very few days. The offspring will bear characteristics (color) of both the mother and the father. The male guppy you purchased may or may not be the father, and you'll have to wait until the pregnant guppy begins to drop her babies to find that you. If he is, all the baby male guppies should bear some resemblance to their father. If they don't, another guppy was the father. Some people will dispose of this initial drop in that case, and wait until the female becomes pregnant again, ensuring the male they purchased is indeed the father and the babies will be the desired colors.
The popularity of the guppy has much to do with the relative ease involved in setting up a breeding program, by selecting males and females having characteristics you're looking for. Bear in mind, the females do not have body coloring, they are more or less translucent. Their fins and tail are colored however. The males have colored bodies as well as colored fins and tail.
Water Temperature Is A Factor - Once a female guppy has become pregnant you can begin to track where she is in the cycle, although most of the easily recognizable signs only become apparent during the past few days before delivery. To become pregnant in the first place, the water temperature has to be in the vicinity of 72 degrees F, The gestation period is somewhat temperature sensitive as well, with a higher water temperature often giving rise to a shorter gestation period. There are times when a pregnant guppy does not give birth at the expected time, and breeders will slowly raise the water temperature to as high as 78 degrees to help things along. This is often done when, due to becoming stressed for whatever reason, the pregnant guppy will not give birth, and unless the babies can somehow be coaxed out of her, she will remain pregnant until she eventually dies.
What To Look For - The initial sign of pregnancy is a dark spot appearing under the tail, near the anus. This is called the gravid spot, gravid meaning heavy, or pregnant. The spot will slowly become darker and enlarge. A day or two before the babies start to drop; you may be able to see their eyes through the female's translucent skin. The female will also start moving more slowly, due to the load she is carrying around, and become quite still as the drop approaches. It is at this point that some will take the female and put her in isolation, in a breeding tank. This is done in part to protect the newborns from being eaten by other guppies which may be in the aquarium. This is a somewhat critical time as far as the well being of the pregnant guppy is concerned. The move is always stressful, and if the water in the breeding tank differs too much from the water in the aquarium, it becomes even more stressful to the fish. It is usually recommended that at least half of the water in the breeding tank come from the aquarium. An overly stressed female may suffer a miscarriage, or give premature birth, or she simply may sicken and die before giving birth at all.
Another crucial point is after the drop. The female may have become sufficiently weakened that she can no longer swim, and may sink to the bottom of the aquarium and die. There is little that can be done in such a situation, but you still may be left with 20 to 30 (or more) healthy babies. It's true that mothers will eat their babies, although this is not always the case. If the mothers have been fed well to begin with, they may not eat their own young, or at least no more than a few. The baby guppies have the ability to swim and feed from the moment of birth, and also have the ability to hide if there is a place to do so. Still, it's a good idea to separate the mother from the offspring if you can do so without stressing the mother too much.