Guppy Fish


Picture by Frank Boston

Guppy fish are also known by the names Rainbow fish and Millionfish. Their scientific name is Poecillia reticulate and they are from the Poecillidae family.

Guppies originated in South American but can now be found in most parts of the world. They adapt well to new locations and usually thrive when they are brought to a new area. In some cases they were brought to new areas to help reduce the number of mosquitoes and in turn the risk of malaria.

Guppies are one of the most popular fish to keep in freshwater tanks. They are hardy, easy to care for and not expensive to buy. This makes the guppy a good choice for amateurs who are new to keeping an aquarium.


Females are larger in size than males, usually 1 to 2.5 inches long, and are a grayish color. Males are typically .5 to 1.5 inches long.

The males have a wider variety of colors, usually red, green and blue, that are displayed as spots or stripes.

Reproduction and Life Span

Females mate with multiple males which is known as polyandry. They give birth to live fish, not eggs. There are an average of sixty in each fry but this can vary greatly. Females can give birth several times in one year.

Young are self-sufficient from parental care at birth but they do group together in schools with other fish.

Typical lifespan in the wild is two years. This varies greatly depending on whether they live in a highly predatory environment.

Diet in the Wild

Guppy fish survive on a varied diet which includes algae, plant particles, mineral particles and larvae of aquatic insects. They will eat more of a specific food when it is more abundant.

They often forage for food in groups.

Keeping Guppies as Pets

Guppies are one of the most popular fish to keep in freshwater tanks but you’ll still need to do some preparation in advance of bringing home your fish.

Preparing Your Tank

Be sure and wash the tank thoroughly before you add water.

Buy a good filter to assure the quality of the water.

Gravel should be rinsed carefully and placed on the bottom of the tank.

Plants are not only decorative but give the guppies places to hide which provides a more peaceful environment for them to live.

Do not add anything that you find in nature to your tank due to the risk of parasites. It is best to buy decorative items from pet stores.

You’ll need to remove the chlorine from tap water before adding fish to your tank. This can be done with a dechlorinate kit which is purchased from a pet store. You can use distilled water instead but you’ll still need to test the ph level. Ideally, the ph level should average around seven.

A heater is needed to keep the water at the right temperature and a thermometer to monitor the temp. The water needs to reach the correct temperature of around 80 degrees before any fish are added. Do not place the tank in direct sunlight as this can raise the temperature too much and cause algae to grow in the tank.

A light will usually come with your tank, if not you’ll need to purchase one. Guppies need at least eight hours of darkness each day. You can put your light on a timer or turn it on each morning and off at night.

Make sure the filter and the heater you purchase are adequate for the size tank you purchase.

Adding an airstone can assure there is enough oxygen in the tank.

It’s preferable to leave the tank for a month before adding fish. This allows the correct amount of bacteria to form in the tank. Add a flake of fish food every three days to start the build-up of bacteria.

Caring for Guppies

Temperature in tanks should be kept at 78 to 82 degrees.

Guppy fish do not like to be kept alone. Always have several guppies in your tank. They are peaceful fish and will even co-habitate with other fish but it’s better to have a one species tank.

They should be fed once or twice a day. Avoid over feeding which will cause cloudy, murky water. All food should be eaten within a few minutes, if not, feed less at the next feeding.

A flake diet is a good start but live food should also be added such as live or frozen shrimp brine, fruit flies, chopped up earthworms, bloodworms or mosquito larva.

Fish tanks need to be cleaned once a week. Remove only about 25% of the water and replace with non-chlorinated water. Use a syphon hose to pick up any debris on the bottom of the tank.

Take out decorations periodically and rinse them off to clear them of algae.

Breeding Guppies

Females can drop an average of thirty to sixty fry at one time – sometimes up to two hundred. When guppies are well fed they usually won’t eat their young but it can still be wise to isolate fry.

Special birthing containers can be purchased for this purpose that are suspended inside the tank. Do not put the pregnant female into the birthing container until she is close to giving birth.

Males will sometimes attach the female as it is giving birth so separate containers are a good precaution.

Breeding guppies is usually quite easy and requires little on your party except moving the female to birthing tank.

If you don’t want your guppies to breed you’ll need to fill your tank with all male or all female fish.

Possible Problems

If your tank becomes too cloudy lower the amount of food you’re feeding your fish. Check the filter and make sure it’s adequate for the size tank you have. You may have too many fish for the size of your tank.

Keep an eye on your fish and notice if they begin to get white spots. This is a sign of skin Ich and can be treated with medicine you buy at a pet store.

If any of your fish look sick remove them and put them in a quarantine tank until they are well.

Remove any dead fish as quickly as possible.

Guppies are beautiful fish that thrive in many conditions. This makes them a good choice for your first fish tank.