Guppy - Poecilia reticulata

Updated May 13, 2020
Author: Mike - FishLore Admin
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The Guppy is perhaps the most popular freshwater tropical fish species and a great fish for freshwater beginners. Although this is a very hardy fish, be warned that it is also a very prolific breeder!

The male is easy to distinguish from the female because the male is usually more colorful with extremely colorful and large caudal fins (tails). The female is usually larger, thicker bodied, with less color and a smaller cuadal fin (tail).

Poecilia reticulata Blue Guppies

They are livebearers which means that the babies are free swimming at birth. At each birth, the female can have anywhere between 4 and 60 or more babies. If left in a community tank, the fry will be quickly eaten if not secured in a breeding net or breeder's box. Sadly, even the parents will partake in the baby fish feast.

Please be responsible and have a plan for what to do with the fry. If you're not interested in breeding them they should do just fine when kept as all males or all females. Or if you've come to this page because you have a tank full of unexpected babies, read the breeding guppies article for more information on what to do. If knowing that the larger fish in the tank are having a feast (as they would in the wild) on the baby guppies bothers you then only keep all males or all females. You may sometimes see some aggression amongst the males but nothing too out of hand.

Also, keep in mind that female guppies can be pregnant when you buy them from the store. Look for the gravid spot by the anal vent or a bulging in the belly area.

They will accept most fish food including vitamin enriched flakes, frozen, freeze dried and live foods. Try to give them a variety of foods for optimum health and coloration. Feeding them live or frozen foods every once in a while should do wonders for their activity levels and general well being.

If you are looking for guppies for sale you can usually find them locally for a few dollars with show quality guppies going for much more. Also check out the buy and sell forum here on FishLore. Several members sell them.

See the Care Sheet on the forum for even more details on keeping guppies.

Latest Guppy Forum Topics

Poecilia reticulata Fancy Guppy Male Poecilia reticulata Black and Red Poecilia reticulata

Guppy Care Details

Scientific Name : Poecilia reticulata

Common Names : Fancy Guppy, Millions Fish, Rainbow Fish

Origin : Originally from an island northeast of South America. They are produced largely on asiatic farms these days.

Care Level : Easy, good for freshwater beginners when you have only one gender. This fish will breed easily in your tank if you plan on keeping males and females in the same tank.

Size : 2 inches (5 cm) - The majority of males reach 2 inches in length. They are much more colorful than the females, generally with larger dorsal fins and caudal fins. Female fancy guppies tend to be 2.5 inches in length.

pH : 7 - 8, harder water rather than softer, and slightly to moderately alkaline

Temperature : 66°F - 84°F (19°C - 29°C)

Water Hardness : 10° to 20° dH,

Lifespan : 3 - 5 years

Origin / Habitat : Central America

Temperament / Behavior : This is a mostly peaceful and hardy fish that is good for beginners. Male guppies can get aggressive with other male guppies.

Keeping them in an aquarium with a hood might be necessary since keepers have reported that their guppies have jumped out of the tank! I had to do some research on this because I had never heard nor seen them jumping. Sure enough, they do with the hypothesis being that they do it to reach all available habitat in Trinidad's mountain streams, which is where they originate. Evolution is amazing.

Breeding : Guppies are livebearers and are not very hard to breed. If you have males and females, chances are you will eventually have babies. Parents will eat their young if not separated. When presented with multiple females to breed with, males seem to prefer the larger females. Read the breeding guppies article for more information if you have a pregnant livebearer or fry.
If you want to try and raise the fry look into investing in a breeding box or breeder net like these:

Breeding Box or Breeding Net

From the caresheet on the forum:
The females are larger around the abdominal area, with the tell-tell purple cresent moon shape in the area directly above the vent. The vent being the opening in which waste is excreted as well as fry are dropped from. Purple cresent moon, also referred to as gravid area, denotes the containment of fetii, or developing baby fish.

Gestation period for poecilia reticulata averages 28-32 days depending on several factors. Water temperature, population density, availability of hiding places, quality of food, stress level, and other species in the tank all can be contributing factors to gestation period's length.

80-82 degrees farenheit water temperature has been known to cause a shorter gestation period. Population density, lack of availability of hiding places, and differing species in the tank all contribute to stress level, which can prolong gestation period, or holding of fry.

Fry become identifiable at about three weeks of age, given proper conditions. Then become reproductively mature around 3 months of age. Females that begin spawning at 3 months of age will have small spawns, but get progressively larger as the fish ages, until about a year of age. At one year of age they will hold steady for a few months and then begin to decline in fry per spawn, until they stop spawning all together. Males will begin breeding as early as 45 days, and continue until death for the most part.

Line breeding, or inbreeding, is often used to set desired traits. Line breeding is defined as breeding fish and their offspring back to each other, so that specific desired (desired by the human in control of breeding) traits become the dominant traits in any offspring of the fish. Generally when line breeding, new, unrelated stock needs to be added no less frequently than every 4th generation.

We've seen some adults learn not to eat their fry, some not have the issue at all, and some that we have agreed will never learn. We theorize the eatting of fry to be strain specific. Any of our primarily black guppy strains eat their fry everytime they have the chance. We've had a cobra strain learn not to eat their fry, much the same way angelfish learn. Of the strains that do not eat their fry, the mothers seem to keep an eye on them for several months, or until they become mature. Females have been seen to go as far as to defend the younger juveniles from adult males in our tanks. The defending was seen more in the platinum or pastel strains than any other.

Aquarium Size : 10 gallon or larger.

Tank Mates : Many, given their peaceful nature.

Diseases : Freshwater Fish Disease - Diagnose, Symptoms and Treatment. Guppies can easily get finrot so keep your water parameters in check and the water very clean via lots of partial water changes.

Diet / Foods : Give them flakes, freeze dried and live foods. Vary their diet for optimum colors and health. Good quality well balanced foods would be a positive, whereas low quality foods could put them in an imbalance of certain needed ingredients. In the wild they consume small insects and bugs that have plant material in their digestive tracks as well as other things, which balance them out. If you want to improve the growth rate and reproductive capabilities of your guppies, this study study suggests supplementing vitamin E.

Tank Region : Middle to top

Gender : Easy to determine. The male will have the larger, more colorful tails.

Fish Lore Forum : Guppy Forum

Photo Credit : Photos copyright

References :

Forum Avatar :
Red Guppy Yellow Guppy

Poecilia reticulata Poecilia reticulata Yellow, Black and Red Poecilia reticulata Yellow and Black Poecilia reticulata

Guppy Comments and Tips

From: Mark via email
Mine is pregnant but I dont know how long and what to do when it gives birth? Please help.
The gestation period for guppies is usually about 28 days but it can take longer for them to have babies. Sometimes up to 38 or 40 days. Some things you can do:
  • Get a Breeder Box or a Breeder Net and place your pregnant female in it.
  • After she has the babies, return the female to the tank but leave the babies in the breeder box.
  • Feed them very small amounts of brine shrimp 3 or 4 times a day.
  • After about 2 weeks you can start to feed them crushed flake food.
  • Figure out what you are going to do when they start to overcrowd in the breeder box. Instead of buying a new aquarium, you may want to get a tank divider for your main tank.
  • When you can put them in with the other fish in your main tank depends on the size of your other fish. The babies should be ready to release into the main tank when they reach 3/4 of an inch in size.
  • Check out the article on breeding them for more information (linked above). Enjoy them and watch them grow.

From: Roland
I have a few pregnant females, and would like to know - how many babies will they be likely to have, and do they give them all at the same time?
The number of babies that a female can have ranges from as little as 4 to as many as 60. The female should pass all of the babies within a few hours. If you don't already have one, look into getting a breeder net or a breeding box to house the female until she releases the babies. See the question above for more information.

From: Bodycount
I just recently purchased 3 females and 1 male. 4 days later I had 4 little babies swimming around. Instead of keeping them I bought 2 red-tail black sharks and 1 albino red-tail in hopes that they would help control the baby population. The little buggers are fast and get away from parent guppies and the sharks whenever they come close to them. I will keep you informed on how its going.
Alrighty then. Sorry to say, but there is a small flaw in your plan, Dr. Evil. The redtail sharks will mostly fight each other because they are very territorial. You will soon have only 1 red tail shark. Tell us how it goes with your therapist.

From: Bob
I have pregnant female and I don't know when she is going to have the babies. Could I leave her in the breeding net until she does?
The gestational period for this fish is usually around 28 days, plus or minus a few days. Generally, the less time the female has to spend in the breeding net the better.

If you have reservations about using the breeder box/net, another option is to use a tank separator and place the female on one half of the tank. Place some breeder grass for the babies to go into after birth on the same side of the tank. The babies will hide in the breeder grass until you can retrieve them. Net the babies and put them into the breeder box and then remove the tank separator. This may be less stressful for the female since she would have more space than if you were to put her into a breeder box. It also makes cleaning up a breeze after feeding the babies since you just have to siphon up the uneaten food in the breeding box.

From: Suzie
What is wrong when your guppies and goldfish start sitting at the bottom of the tank and their gills are pumping fast along with their mouths, then they will start to lay on their sides swim around and back to their sides then after appx 3-4 days they have passed on to fishy heaven. What could be causing this?
It could a few different things but most likely there is a problem with the water in your tank. Have you checked the ammonia, nitrite, nitrate and pH levels? If your tank is new then it probably has not cycled yet. For more information on this please read about the Aquarium Nitrogen Cycle. This is a very important process that you must understand if you want to be successful at keeping fish.

From: Jenn
I woke up the other morning and to my surprise found 8 babies. I have no idea how long they have been there. I had to treat the other fish for ick so I removed them from the tank before the treatment began. All the other guppies have ick. Do you think the babies will too?
Getting ick in your tank usually means that something is out of whack with your water parameters, you recently introduced a new fish, or you have a new system with all new fish. You'll need to check the ammonia, nitrite, nitrate and pH levels. If this is a new tank, be sure to read up on the Nitrogen Cycle. Also read this article; Sick Fish, What Do I Do? The baby fish will get ick too so you will need to treat them right away if you don't want to lose them.

From: Elizabeth
Having a hard time deciding to breeding them or not? Well, here are some questions that you should ask yourself:
  • Is your tank big enough?
  • Where will they grow?
  • Where will they go?
  • But most inportantly, is it necessary to breed them?
Hope this works!

From: Megan
I have a new tank that hasn't completed the Nitrogen Cycle yet and I was wondering if they would do okay.
They may have a chance of making it through the cycle if you stay vigilant with those water changes to keep the ammonia and nitrites from getting too high. The downside is that you're prolonging the aquarium nitrogen cycle by doing the water changes. Read the page on the nitrogen cycle for ways to kick start this process. Look into the Bio-spira product for the nitrogen cycle.

From: StanMan
I have a pregnant female fancy and I have no idea how or what to do when the babies are released. Would it be ok if I leave the fry in a fish bowl until they are big enough to get into the tank with the parents? The female looks REALLY pregnant. Its stomach is about almost a centimeter slumping down and the triangle is really dark and big. Will it breed soon?
Sounds like the breeding has already happened. It's difficult to say when she'll drop the babies. Get some breeder grass or use a breeder net to capture as many of the babies as possible. If you don't you risk the other fish in the tank eating the babies. A bowl may not work very well (need a heater and sponge filter) in order to raise these baby fish until they are big enough to re-enter the tank. They need very frequent small feedings with quality fish fry foods and good water conditions provided via frequent partial water changes.

From: Ro
In my experience, they will get along fine with most fish. However, don't house them with male OR female Betta fish. I once made the mistake of adding a female betta to my tank, (assuming from what I'd heard from the shopkeeper that they didn't nip!) and I had some very torn fins! The betta is now back where she belongs, in the shop, and mine are healing nicely. I keep mine with platys and cherry barbs. They all get on fine, great fish with a peaceful community. I've also kept them with black and balloon mollies, otos, and corys without any problems.

From: Mommy of Many! - Baby Guppies
Ok, I had a pair but the dad got beaten up by the other tank mates and died. I took mom out and put her into her own little tank. I figured she was prego and she was as a couple of weeks later she had about 20 babies. I removed all the babies and put them into their own tank. It has been about a month. I have cleaned moms tank completely (as in mom was in a measuring cup on the counter and the tank completely empty), not even gravel. I looked today and saw mom chasing around another group of babies. Now I need to know why? There has been no male at all in almost 2 months yet I have babies. Are guppies capable of asexual reproduction?
The female can have several batches of fry from just one fertilization from a male.

From: Maddy - New Tank
I want to have guppies and other livebearers in my community tank that is cycling. I have heard they need salt and wondering if the salt would harm the other fish I put in too, or if livebearers can cope without. Looking forward to an answer!
Oh man, you don't need to subject fish to the cycle nowadays. There are products on the market to quickly cycle a tank. Check out the aquarium nitrogen cycle page for more info on these products. By subjecting your fish to the cycle you are most likely shortening their life spans if they even survive the aquarium cycle at all. As far as salt goes, I wouldn't put it in the tank unless it was a Molly fish tank. Most commonly available livebearers will do just fine without the addition of aquarium salt.

From: The Giver
I disagree with the aquarium salt in the above posting. I agree that it is great for mollies. However, it has been my personal experience that it does wonders to prevent ick and other diseases when added even less than monthly and in small quantities of course to the tank. I have never had a problem. If anything, I have an overbreeding problem!

Still have questions?
Jump on the forum and ask your question! Go here: Guppy Forum