Guppy fish care guide

Guppy fish (lat. Poecilia reticulata) is a renowned tank fish. Even people who are not into aquarium husbandry know about this fish, not to mention aquarists. Each of them has surely had a guppy fish in a tank even just once. Some aquarists started their hobby from buying a couple of fish and even now they have some splendid selective breeding species. To answer all the questions about this fish we’d have to write a book, but we’ll try to discuss the most common ones here, in this article.

Habitat in the wild

Guppy got its name in the name of English priest and scientist Robert John Lechmere Guppy, who in 1886 made a report to Royal Society, in which he told about the fish that spawns juveniles instead of eggs.

Poecilia reticulata habitat is in freshwater and brackish water basins of Venezuela, Guiana, to the North of Amazon river, on the North of Brazil, Barbados islands and Trinidad.

As a rule, the fish dwells in clean flowing water, but they also like brackish nearshore waters, but not salty seawater. Feeds on worms, larvae, bloodworm and various small insects. Due to this peculiarity the fish was acclimatized in all continents (guppy was brought to warm water basins all over the world to fight with larvae of malarial mosquito).

In the wild males are more brightly colored than the females, though their colors is a far cry from those tank species obtained after selective breeding.

Scientific NamePoecilia reticulata
Common NamesGuppy; guppy fish; millionfish
Range and habitatVenezuela, Guiana, Brazil, Barbados islands, Trinidad
Size 3–6 cm (1.2–2.4 in)
Lifespan2-3 years
Ease of keepingEasy
Minimum tank size5 gallons and more
Temperature72–79°F (22 – 26 °C)
Water hardness5-20 dGH


Intraspecific variety of the fish colors, ability to breed fast and easily, allowed breeders to create unbelievable diversity of breeds with all possible types of patterns and color combinations.

Is a small sized fish with an elongated body. Like platy, molly and swordtail they are from Poeciliidae family, who have teeth on their maxilla and mandible.

Males are typically 1.5–3.5 cm (0.6–1.4 in) long, while females are 3–6 cm (1.2–2.4 in) long. The male body is elongated, thin and a bit flattened from sides. The female also has elongated body, but its back side is more flattened from sides. Males are much brighter colored and they also have gorgeous tails and fins, while females have rather pale coloring and short fins.

Anal fin of male was modified into a reproductive organ – gonopodium. The female has a bit enlarged abdomen and you can see eggs in its anal region.

Her fins are always proportionally smaller than that of the male. Most females from natural habitat have gray scales with pronounced diamond shaped pattern, which gave the name to the strain: reticulum (in Latin it means reticle, net).

Lifespan is about 2 years in average. Provided with good tank conditions the fish can live up to 3 years in a tank. What we should mention, is that its lifespan reduces as the tank water temperature rises, due to the growth of metabolism processes rate.

During many years of keeping guppy fish in tanks and after thorough selective breeding there were obtained lots of strains that require specific and quite complicated care.

Nowadays, it’s quite difficult to classify guppy, since as a result of numerous hybridization each year we get more and more new breeds.

Main parameter used for classification is the color of its body (mainly it’s male coloring), then comes the size, shape and color of its fins.

The fish gets its name exceptionally due to the color of its tail fin: so, if guppy fish has yellow colored body and red tail, it’ll be called a red guppy.

Without exception all wild female species have transparent and colorless fins and their body is grayish with green, blue or olive-green tint.

Difficulties in keeping

It’s an excellent fish both for beginners and professionals. It is small, active, nice, it breeds easily, not demanding as for the diet and keeping and we can continue this list on and on.

However, we’d like to warn the beginners against buying bright fish types obtained after selective breeding. How to define such a fish? If all fishes in a tank are of one color, males have long and uniformly colored fins, then these are demanding guppy fishes.

If both males and females vary and they are differently colored, then these are the fishes exactly for the beginner aquarist.

The thing is that guppy fish become very beautiful after selective breeding, but at the same time they become rather demanding and loose all their initial advantages.

Fancy guppy have low immunity and require special care. Therefore, if you decided to try yourself in aquarium husbandry, it’s better to get the simplest multicolored guppy fishes.

They will delight your eye as good as any selective breeding species, but they’ll live much longer and cause less problems.

At that professional aquarists can get these demanding hybrids, though they should be carefully sorted and even more carefully bred and taken care of.

Care and keeping in a tank

Tank Size

Small, but excessively active fish requires a small sized tank. The one of 5 gallons (19 L) capacity will perfectly do for 3 guppy fish. The fish is not demanding, but it gets its maximum beauty only at favorable tank conditions.

Offspring of the most high-bred parents in small tank still won’t get neither their brightness, nor the size of their fins. Can live even in a glass of water, but this will be a survival, not a real life.

When choosing a tank, you should take into account their high fertility. Number of the females in the tank has to be 2-3 times larger, than that of the male.

Otherwise, the females will be stressed all the time due to the male fish haunting them. It is acceptable to keep only male in the tank, if you don’t need any offspring.

Water Parameters

Though tank water temperature range for keeping guppy is quite wide (allowable range is 73–82°F (+23—28°C), the fish survives in the range from +14°C to +33°C), you should keep the temperature stable 72–79°F (22 – 26 °C).

At low temperatures fishes grow larger, live for about 3—3,5 years, but at that they can easily get ill. Gestation period of female species gets longer and the juveniles are born rather large.

If tank water temperature is lower than 65°F (+18°C) the eggs development can stop at all and fish reproductive function is at rest.

At high temperatures lifespan is about a year or less, they don’t grow large. Gestation period of the female becomes shorter and the juveniles are born small sized.

When keeping the fish at the lower temperature range 86-91°F (+30—33°C) “self-castration” of the fish is possible due to loss of activity and ability to spermatozoon fertilization.

Optimal tank water parameters are: gH up to 25°; pH within 6,5 – 8,5, but it’s better to be 7,0. Guppy fish adapt better to hard water and they stand brackish water quite well. Abrupt changes of tank water temperature and parameters (pH, gH) take toll on male fins.

That’s why you should renew water more often, but in small values (not more than 1/3 of the whole volume). You should also avoid strong water flow in a tank.


It’s not a good idea to put plants with large and coarse leaves into a tank. It’s better to put some tank plants with small leaves without sharp edges, that can harm the fins and tails.

For the same reason, it’s not worth putting some rock shelters or other sharp edged objects like snags, stones etc. into the tank with fishes.

We should also mention, that abrupt change of tank water temperature and chemical content (pH mainly) may become fatal to guppy fish adapt as well as keeping them in a tank with old water (without water renew) for a long time, which decreases their persistence to diseases.

Dark colored small grained gravel is a good bottom substrate for the tank. This kind of substrate will only lay emphasis on the beauty and bright colored patterns.

Smooth snags and stones will make the tank look natural. Moderate tank illumination is preferable for guppy, but not more than 12 hours a day.

Fishes favor tanks with fresh, regularly renewed water, with sufficient space for swimming, light water flow and tank plants with small sectile leaves or thick floating roots.

Test plant, that is a good indicator of tank conditions quality in a specific tank is water sprite (Ceratopteris thalictroides). If the fern grows next to the tank bottom, it means that tank conditions are good. If they get worse, roots of the plant start to rot and it floats up to water surface or even dies.


It’s desirable to use a water filter (internal one will be quite enough), though if you have an external one, this will do as well. But it’s better to close its apertures with additional fine mesh, because a powerful filter can not only suck the juveniles inside it, but the adult fish, too.

We can’t call guppy a schooling fish, but there is almost no point in keeping just one fish couple. Since it’s a small sized fish, you will not notice a little number of them in a tank. The idea is simple – the more guppy you have in a tank, the more impressive and beautiful they look.


Guppy fish adapt is easy to feed. It eats various food – artificial, frozen, live. The fish gladly feeds on flakes, pellets and other artificial food, but it’s better to choose food of famous trademarks.

As for the live food, favors bloodworm, tubifex, brine shrimp, corethra. It’s important to keep in mind, that guppy fish has small mouth and stomach and the food should be also small sized.

Therefore, the best thing is to feed 2-3 times a day with portions that the fish can eat in 2-3 minutes. Also fancies food with high vegetable content.

Thus, except common food flakes get some flakes with vegetable supplements and feed with them twice a week to ensure healthy gastroenteric tract of the fish and high immunity.

Tank mates

Is a very peaceful fish that causes no trouble to its tank mates. Keep in mind, that this fish can and will eat its juveniles. Even the female after spawning will do this.

The guppy fish can be hurt by many other fishes, especially large and predator ones, which treat fish only as food. So, the conclusion is, that fishes like green terror, angelfish, jack dempsey won’t do as tank mates.

The same is about fishes which will nip fins of males. These are — tiger barb, black skirt tetra, red-eyed tetra.

Guppy fish get along well with peaceful and small fishes like dwarf gourami, bristlenose pleco, white cloud mountain minnow, harlequin rasbora, cherry barb, molly and platy.

Gender differences: male vs female

It’s quite simple to see between guppy female and male. The latter are smaller, thinner, they have large fins and their anal fin was modified into gonopodium (roughly said, this is a tube by means of which males of live-bearing fishes fertilize female).

Females are large, they have rounded and pronounced abdomen and as a rule they have quite pale coloring.

Even among the guppy juveniles you can define males and females at rather early stages, because male are the first to get their full coloring.

Two males and female guppy fish
Female guppy fish


One of the simplest fishes to breed is guppy fish. The thing is, that this fish is a live-bearing one. It means that the fish carries eggs inside its abdomen and spawns fully formed juveniles.

During the first hours of their life juveniles will lay down and hide somewhere, but very soon they will start to swim and feed.

All you need for guppy breeding is… a male and a female. No, it’s even easier – one active and young male is enough to perform courtship over 3-5 females non stop.

Which means that for successful breeding you can keep one male for 3-5 females, though there can be more males in a tank, because they don’t fight with each other, they only compete.

You may see the male haunting the female one for a long time, but this is ok and there is nothing you have to do about it.

The thing is that during such haunting process the male fertilizes the female and soon you’ll have juveniles in your tank.

What do you need for breeding? Fresh and clean water, quality and good food and a couple of hetero fish. As a rule, guppy fish breed quite successfully in a common tank.

But they also eat their juveniles and their tank mates either, which means that you should put pregnant female fish into a separate tank.

How to get that female is carrying eggs? The spot near the female anal orifice gets darker and the darker it is, the sooner the fish will spawn.

Put the female into a separate tank with the same water parameters and tank plants, where the juveniles can hide from her (yes, he is going to eat her kids). When the time comes, the female will spawn without issues.

Gestation period of the female lasts about 21-40 days depending on the tank water temperature. At the end, according to the fish age and size, it spawns from 10 to 200 juveniles.

One mating is enough for several fertilizations: the female spawns juveniles in portions – each 1-1.5 months. There were numerous cases when the female fish continued spawning 12-14 month later after mating.

That’s why virgin female grown separately from male are used for selective breeding.

You should put the female away from the tank right after spawning. Juveniles care is the same simple, as that for the adult fish. Feed them with milled branded food (the same that you feed adult with).

Though it’s better to use special branded dry food for juveniles. You have to clean the tank with juveniles often to avoid food leftovers rotting. You can put some snails into the tank – apple snails or ram’s horn snails, for example.

They won’t harm the juveniles, but they’ll eat the food leftovers.

It’s important to keep the tank water clean, but remember, that you can’t renew large amount water at one time.

The juveniles are small and weak, therefore changing of large water amount is dangerous for them. It’s better to renew about 10% of the total water volume once in 1-2 days or 25% of water once in a week.

Tank water temperature is crucial for juveniles and you must keep it about 24-26.5 C. Provided with proper care and diet the juveniles grow fast, so in 1-1.5 months they start getting their coloring.


Why do guppy fishes die?

We can’t give you just one right answer for this question. Each case is a unique one. But more often than not the reason of the fish death is improper keeping.

You must pay special attention to how often you renew water in a tank and how often you feed guppy. Everything is simple – food leftovers are like rubbish in your house, which is lying somewhere under the furniture and rots.

When such rubbish accumulates in the tank – the fish gets ill. You can help it by cleaning the tank bottom and renewing tank water.

Which fishes can be guppy tank mates?

Some of them we have already mentioned above, but also you may read the article, – every fish that is in the list will do as a tank mate.

How to identify that female is pregnant?

Normally, female spawns juveniles once in a month, but the terms may vary depending on the tank water temperature and conditions. Remember when was the last time that the fish spawned and watch the fish. The spot on the abdomen of guppy fish that is ready to spawn becomes darker (these are juveniles eyes).

How does guppy breathe?

Just like all other fishes it breathes with oxygen dissolved in water. So, don’t forget to turn on aeration and water filtration.

How long does guppy live?

The fish lives for about 2 years. It depends on tank conditions and water temperature. The higher the temperature is, the shorter is the lifespan. Although, some live up to 3 years.

How often should I feed guppy?

You must feed the fish every day with small portions of food 2-3 times a day. For example, in the morning and in the evening.

Once in a week you can organize hunger day for the fish, but keep in mind that they will actively look for food and their own juveniles will quickly become their prey.

Why does guppy tails get torn?

There may be many reasons for this, but the most spread one is old water in the tank. The water accumulates ammonia and nitrates and these poison the fish and destroy its fins. Thus, regular water renew will save you from this problem.

However, if guppy lost its tail, this is a warning sign – either someone is nipping its fins and you have to study carefully the tank mates again, or the fish is ill with some infectious disease and you must examine other fishes in the tank even more closely.

Why is guppy tail gummed up?

Again this is either due to dirty, old tank water or some infection. Try to renew 20% of water once a week and monitor state of other fishes in the tank.

Why does guppy have a curved spine?

You can encounter such fishes among almost all species. As a rule, this is an inborn defect. Though, if this has happened to an adult fish, it may be due to the fact, that the fish is kept in a small tank with large number of tank mates.

Why does guppy spawn only female?

There is no full and complete reply for this question yet. Possibly, some laws of nature get on the stage, when there is an exceeding number of males in the tank and the population compensates the female number to save itself.

Can I have only one guppy in a tank?

Yes, you can, but it looks pretty sad…since, this is an active and joyful fish that likes company. If you are looking for an appealing, not demanding fish that easily lives alone, you may consider getting a betta fish.

Does guppy need oxygen and water filter?

Well, it’s not necessary, but it’d be good if you have them. You can get inexpensive internal water filter with a sponge. It’ll do the job quite well and won’t suck the fishes inside it. Keep in mind, if you have bought a filter and installed it high (to make the tank water surface move), you don’t have to buy aeration – you don’t need it at all.

Does guppy need bottom substrate and tank plants?

This is up to you. It is easier to clean an empty tank, but it doesn’t look nice. The juveniles won’t survive in it and also the adult fish like swimming among the tank plants. So, my choice is a tank with bottom substrate and plants.

Does guppy need illumination?

Fishes don’t need any light in general. The light that gets into the tank during a day is quite enough for them. These are tank plants which need light to grow.

Does guppy spawn eggs?

No, this is a live-bearing fish. Which means that the juveniles are born fully formed and ready to swim. Sometimes the juvenile may come out inside the egg, but it gets torn and the juvenile starts to swim. Occasionally, juvenile may have a yolk bag which it eats fast.

Does guppy sleep?

Yes, they do, but not like humans. This is more like an active rest, when at night the fish become less active, but still they continue swimming.

Also it is better to turn off the lighting at night, though many aquarists don’t do this. But it is dark at night in the wild, isn’t it?

How many juveniles does guppy spawn?

This depends on the female – on its age and size. Usually, there are about 30-50 juveniles, but it can be even 200 sometimes.

How long does it take a juvenile to grow?

Provided with good tank conditions it grows very fast. Males become reproductive at the age of 2 months and females when being 3 months old.

Can I keep guppy is seawater?

No, you can’t. Although, they can stand living in brackish water, they’ll die in seawater. This is a freshwater fish.

Why do guppy swim on the tank water surface?

They breathe with oxygen dissolved in water and there is not enough oxygen in your tank. Why? Possibly, it is too hot in a tank or you haven’t cleaned it for a long time or maybe the tank is too crowded. You must definitely turn on aeration and water filtration (move the filter closer to the water surface to improve gas exchange) and add a portion of fresh water into the tank.

Why does guppy jump out of the tank?

They can do it both accidentally and because the water in the tank isn’t good. For example, the water hasn’t been renewed for a while or the bottom substrate wasn’t cleaned. Insufficient amount of dissolved oxygen in the tank water may also be the reason (you can read about this above).