Guppy Guide: How to Care

Guppy (Poecilia reticulata) is probably the most famous aquarium fish in the world. It is well‑known to both beginners and seasoned aquarists alike. Many people start with guppies (I was one of them as well J). Over the years, dozens of color and fin varieties have been developed, which makes guppies even more popular.

In short, guppies are small, peaceful, and extremely easy to keep. They breed like crazy, eat almost anything, and can live in a wide range of water parameters. Therefore, If you are looking for a colorful and active fish that will not cause you much trouble – guppies are the perfect choice!

Whether you are a beginner or just want to refresh your knowledge, this guide will help you keep these beautiful fish healthy and happy.

Quick Notes about Guppies

A bit of History

History of Guppy began in 1859 when a German ichthyologist named Wilhelm Peters got a few fish from Venezuela. Since they hadn’t been described before, he named them Poecilia reticulata.

Other ichthyologists were also getting them from different places. For example, at that time a schoolteacher Robert John Lechmere (1836-1916) sent some fish from Trinidad to the British Museum. They thought it was a new species and named it Girardinus guppyi, after the man they thought discovered it.

Finally, in 1963, German ichthyologists found the original record from their colleagues and confirmed the name Poecilia reticulata. So for almost a hundred years, guppies had a different name.

Etymology

The genus  name “Poecilia” was derived from the Greek word poikilos which means ‘variegated or variable’,.

The species name “Reticulata” is Latin for “net‑like”, referring to the reticulated scale pattern.

Distribution and Natural Habitat

Guppies are native to Trinidad and Tobago, as well as to parts of Venezuela, Guyana, Barbados, and several other Caribbean islands.

This species is not demanding and can live in clean, running water from small streams as well as drainage ditches and ponds. Interestingly, they can also tolerate brackish water, but not full seawater.

Description

Wild‑type guppies are small and not very flashy. Natural populations are highly polymorphic to the extent that no two individuals are alike. The patterns consist of a mosaic of spots or patches varying in color, size, and position.

Males are smaller than females, grow about 1.5 inches (4 cm) in length, and have brighter colors. They stop growing when they attain maturity. Females reach about 2.5 inches (6 cm) and are mostly grey‑olive with a dark spot near the anal fin.

Distinguishing characteristics of guppy:

• Body shape: Males are slender and smaller. Females are larger, more deep‑bodied, and have a rounded anal fin. The male’s anal fin is modified into a pointed tube called a gonopodium, used for mating.
• Fins: Guppies have no dorsal spines. The dorsal fin has 7–8 soft rays. The anal fin has 8–10 soft rays. There are no spines anywhere. All fins are soft.
• Color: This is where guppies really shine. Males show an amazing variety of colors – black, white, orange, yellow, green, and iridescent blues and reds. They can have spots, stripes, speckles, and patterns that change depending on the strain. Females are much simpler: silver‑grey, sometimes with a slight yellowish tint, and a dark spot near the anal fin (the gravid spot).

Through selective breeding, dozens of domestic strains have been created. They differ in fin shape (round tail, lyretail, swordtail, etc.) and colour (red, blue, green, yellow, albino, cobra, snakeskin, mosaic, etc.). Because guppies cross‑breed so easily, new forms appear constantly.

Lifespan

Guppy life expectancy is about 2–3 years. If you are lucky, some fish may live up to 5 years.

Their lifespan strongly depends on water temperature – in warmer water (above 79°F (26°C)) their metabolism speeds up, they grow smaller and live for about a year or even less. In cooler water (68°F-72°F or 20–22°C) they live longer but are less active and may not breed as readily.

Behavior

Guppies are very active and curious fish. They are not a true schooling species, but they feel safer and look more impressive in a group. The more guppies you have, the more beautiful they appear.

Although Guppies are generally peaceful, but they can sometimes be a bit nippy, especially if they are kept in too small a group or if the males get too excited while chasing females. It is not very common, but it can happen and need to be taken into account.

They are also known to be jumpers. If something startles them or if the water quality is poor, they can easily jump out of the tank. That is why a tight-fitting lid is always a good idea.

Features:

• Social: Yes
• Activity: Very High
• Placement: Top and middle dwellers
• Peaceful: Yes
• Nippers: Sometimes
• Jumpers: Yes

Feeding

Feeding guppies is very easy. They are omnivores and feed on a variety of food sources, including zooplankton, detritus, and even algae.

In aquariums, they will eat artificial, frozen, live, and dry food. They accept fish flakes, granules, and other commercial foods with pleasure:

• spirulina,
• brine shrimp (artemia salina),
• Artemia nauplii,
• daphnia,
• fruit flies,
• moina,
• detritus worms,
• vinegar eels,
• mosquito larvae,
• cyclops, etc. 

Because guppies have a small mouth and stomach, it will be a good idea to feed them 2-3 times a day in small portions that they can finish in 3–5 minutes.

This mimics their natural feeding behavior and helps prevent overfeeding and digestive issues.

Tip: A varied diet (flakes, brine shrimp, daphnia, bloodworms, spirulina) improves their color and health.

Interesting fact: In nature, guppies feed on mosquito larvae, small insects, algae, and detritus. Because they eat mosquito larvae, they have been intentionally introduced to many tropical regions to help control malaria. As a result, Poeciliids are established invasive species worldwide.

Features:

• Diet Type: Omnivore
• Food Preference: Meat
• Feeding Frequency: Daily

Are Guppies Plant Safe?

Yes, guppies are completely plant‑safe. They do not eat healthy plants. In fact, a heavily planted aquarium is highly recommended! Floating plants are especially useful for fry.

Tank Requirements

Tank Size:

A small aquarium of 5 gallons (20 liters) is enough for 5 guppies. Some follow the rule “1 liter per 1 cm of fish”, but obviously the more space, the better.

Important: DO NOT add fish to the tank if it has not been cycled yet. Although, for the most part, they are pretty tough and hardy high ammonia and nitrates will kill them.

Related article:

• Tank Lids: Necessary or Optional? Pros and Cons

Water Parameters:

• Temperature:72–77 °F (22–25 °C)/ They can tolerate 66–84 °F (19–29 °C) but it will affect they lifespan and breeding rate.
• pH:0–8.0 (range may be 5.8–8.5)
• Hardness:12–18 °GH (up to 25)

Filtration and Aeration:

Guppies breathe oxygen dissolved in the water, so aeration and filtration are necessary. If you use a powerful filter, cover the intake with a fine net. In this case your fry won’t be sucked in. A sponge filter is a very safe choice for guppy tanks.

Perform weekly water changes of 25% of the tank volume.

Lighting:

Lighting is not critical at all.

Guppies do well in any light, from bright to dim. However, moderate lighting helps plants grow and enhances the fish’s colors.

Related articles:

• Top 10 Low Light Aquarium Plants. Pros and Cons
• Advanced Guide to Planted Tank Lighting

Decorations and Hiding Places:

Live plants, artificial plants, driftwood, rocks, and caves are not essential but provide shelter for fry and reduce stress. The most important decoration is plants (real or artificial). As I have already said, Floating plants are especially beneficial.

Acclimation:

When you bring guppies home, do not simply pour them into the tank. Float the bag in the aquarium for 15–20 minutes to equalize temperature.

Then add small amounts of tank water to the bag every 5–10 minutes for about 30–45 minutes. Finally, gently release the fish (do not pour the bag water into the aquarium). This slow acclimation prevents shock.

Sexing Guppies

It is very simple to distinguish male from female.

Even juveniles can be sexed early – the first fry to show color are usually males.

Breeding Guppies

Guppies are among the easiest fish to breed. They are ovoviviparous (livebearers). The female carries fertilized eggs inside her body and gives birth to live, free‑swimming fry.

Mating:

Keep one male per 3–5 females. The male uses his gonopodium to fertilize the female internally.

Interesting fact: In nature, males cannot have color patterns which are too conspicuous, or they will be consumed by predators; but they cannot be too inconspicuous, or females will choose other males.

Pregnancy and Birth:

Gestation lasts about 21–35 days, depending on temperature.

A few days before birth, the female’s belly becomes squared off, and she may hide among plants.

Place a pregnant female into a separate breeding tank or a floating breeding box with fine‑leaved plants (e.g., Java moss) to protect the fry from being eaten by the mother. After giving birth, return the female to the main tank.

Note: A pregnant female develops a dark spot (the “gravid spot”) near the anus. The darker the spot, the closer she is to giving birth.

Number of Fry:

According to the study, a female usually gives birth to 12–60 fry, but large females can produce up to 100. New born fries are transparent or blackish in color/ They usually have slender body with jaws developed on mouth.

They grow very fast, attain sexual maturity at 8 -10 weeks and reach full size in 6 months.

Guppy Fry Care:

The first hours, fry will lie at the bottom or hide among plants. After that, they start swimming and eating.

Feeding Fry:

• First 2–3 days: infusoria, liquid fry food, or finely crushed egg yolk.
• After that: microworms, baby brine shrimp (Artemia nauplii), and high‑quality powdered fry food.
• After 2 weeks: crushed flakes, small daphnia.

Feed fry 4–5 times a day in tiny portions.

Water Quality:

Fry are sensitive to water changes. Do not change large amounts at once. Change 10% of the water daily or 25% once a week.

Temperature:

Keep the water at 24–26.5°C (75–80°F) for optimal growth. With proper care, fry grow quickly. They start showing colour in about 1.5 months.

Sexual Maturity:

• Males become mature at 2 months.
• Females become mature at 3 months.

Tankmates (Compatibility)

Guppies are generally peaceful fish and do not cause trouble to neighbors. However, they can be easily harassed or eaten by large and predatory fish.

Good tankmates:

• Danio rerio,
• Dwarf cichlids (Apistogramma agassizii),
• Harlequin Rasboras,
• Dwarf Ember Barbs,
• Neon Tetras,
• Pygmy Cory, 
• Clown Killifish, 
• Least Killifish,
• Otocinclus, etc.

Avoid:

Keep Guppy away from most types of crayfish and freshwater crabs.

Even African Dwarf Frogs may try to catch them due to their small size.

Bad tankmates for guppy:

• Angelfish, cichlids, goldfish
• Tiger barbs, large barbs
• Bettas (may attack or be attacked)
• Any fish that can fit a guppy in its mouth

Shrimp:

It is a big NO!

Unfortunately, breeding dwarf shrimp in the same tank with guppies is almost impossible.

Guppies usually do not touch adult shrimp, but they will eat all shrimplets. If you still want to keep them together, provide dense moss and hiding places, and be ready for losses.

Snails:

Guppies are perfectly compatible with any freshwater snails. Snails help clean the tank and do not bother the fish.

Potential Problems and Diseases

Why do tails shred?

Common reasons:

• Old water with accumulated ammonia or nitrates – do regular water changes.
• Sharp change in water parameters.
• Injury from aggressive tankmates or decorations.
• Poor feeding (lack of vitamins).

Guppy lost its tail

If the tail is torn off, find the culprit – either a fish or a sharp object. If the edges are ragged and white, it may be a bacterial infection (fin rot). Treat with appropriate medication and improve water quality.

Why does the tail stick together?

Causes: old/dirty water, bacterial infection, or poor nutrition. Start with 20% weekly water changes and observe.

Curved spine

Possible reasons:

• Birth defect.
• Too small aquarium with overcrowding.
• Old age.
• Fish tuberculosis (mycobacteriosis) – a serious disease. Isolate affected fish to prevent spread.

Guppies swim at the surface

They are gasping for oxygen. Causes: high temperature, poor aeration, dirty water, or lack of surface movement. Turn on aeration, place the filter outlet near the surface, and do a partial water change.

Can Guppies Live in Saltwater?

No. Guppies are freshwater fish and will die in full seawater. They can tolerate slightly brackish water, but not marine conditions.

Buying Guppies

When buying guppies:

• look for active fish with intact fins and bright colors,
• avoid fish that are pale, lethargic, or have clamped fins,
• ask the seller about the water parameters they were kept in – sudden changes can cause stress.

It is best to buy guppies from a local breeder rather than a pet store, because store‑bought fish often arrive stressed and may carry diseases.

Important: Always quarantine new guppies for 2–3 weeks before adding them to your main tank!

In Conclusion

Guppies are gorgeous, undemanding, and perfect for beginners. Their active behavior and incredible variety of colors make them a joy to watch. They are easy to breed and will quickly fill your tank with life.

Just remember the rules:

• provide a clean, well‑planted aquarium,
• feed a varied diet,
• and avoid aggressive tankmates.

With a little care, your guppies will thrive for years.

Frequently Asked Questions

How does guppy breathe?
Like all fish – they absorb oxygen dissolved in water. Do not forget aeration and filtration.

How long do guppies live?
About 2–3 years, but it depends on conditions and temperature. Higher temperature shortens their life. Some fish live up to 5 years.

How often should I feed guppies?
Daily, 2–3 times a day in small portions. Once a week you can skip a feeding, but the fish will then actively hunt their own fry.

Can I keep guppies in a bowl?
It is not recommended. Bowls are hard to maintain, have poor gas exchange, and cause stress. Use a rectangular aquarium.

Do guppies need a heater?
If room temperature stays within normal parameters, a heater is not essential. However, a heater helps keep the temperature stable, which is healthier for the fish.

Why do my guppies keep dying?
Most common reasons: poor water quality (high ammonia and nitrates), sudden temperature changes, overfeeding, or disease. Test your water and review your maintenance routine.

References

1. Poeser, F. N., M. Kempkes and I. J. H. Isbrücker, 2005- Contributions to Zoology: 97-115
   Description of Poecilia (Acanthophacelus) wingei sp. from the Paría Peninsula, Venezuela, including notes on Acanthophacelus Eigenmann, 1907 and other subgenera of Poecilia Bloch and Schneider, 1801 (Teleostei, Cyprinodontiformes, Poecilidae).
2. Bischoff, Robert J., James L. Gould, and Daniel I. Rubenstein. “Tail size and female choice in the guppy (Poecilia reticulata).” Behavioral Ecology and Sociobiology17, no. 3 (1985): 253-255.
3. Schories, S., M. K. Meyer and M. Schartl, 2009- Zootaxa No. 2266: 35-50
   Description of Poecilia (Acanthophacelus) obscura sp., (Teleostei: Poeciliidae), a new guppy species from western Trinidad, with remarks on P. wingei and the status of the Endler’s Guppy.
4. Bragança, Pedro & Guimarães, Erick & Brito, Pâmella & Ottoni, Felipe. (2020). On the natural occurrence of Poecilia reticulata Peters, 1859 (Cyprinodontiformes: Poeciliidae). Cybium: International Journal of Ichthyology. 44. 309-316. 10.26028/cybium/2020-444-002.
5. Endler, John A. “Natural Selection on Color Patterns in Poecilia Reticulata.” Evolution 34, no. 1 (1980): 76–91. https://doi.org/10.2307/2408316.
6. Reznick, David, and John A. Endler. “The impact of predation on life history evolution in Trinidadian guppies (Poecilia reticulata).” Evolution(1982): 160-177.
7. Ahmed, Jubayer. “Breeding biology of guppy fish, Poecilia reticulata (Peters, 1859) in the laboratory.” Journal of the Asiatic Society of Bangladesh, Science(2014).