How To Tell If a Guppy Is Male or Female? - "Guppy coppia gialla" by Marrabbio2 is licensed under CC BY-SA 3.0.
How To Tell If a Guppy Is Male or Female? - "Guppy coppia gialla" by Marrabbio2 is licensed under CC BY-SA 3.0.


Guppies, those captivating and vibrant aquatic gems, have fascinated aquarium enthusiasts for generations. Their exquisite colors and lively personalities make them a popular choice for both novice and experienced aquarists. One fundamental aspect of guppy care, which often intrigues beginners, is understanding how to tell if a guppy is male or female. Recognizing the gender of your guppies is not only a delightful endeavor but also a vital part of creating a thriving guppy community. In this article, we will not only unravel the mysteries of guppy gender identification but also delve into various facets of guppy care, breeding, and raising fry. Let’s embark on this journey to explore the enchanting world of guppies and equip ourselves with the knowledge needed to raise these remarkable fish.

How To Tell If a Guppy Is Male or Female?

So, how to tell if a guppy is male or female? You can determine the gender of a guppy (Poecilia reticulata) by examining various physical and behavioral characteristics. Here are some methods to distinguish between male and female guppies:

Anal Fin

  • Male Guppy: The anal fin of a male guppy is modified into a long, slender, and pointed fin known as the gonopodium. It looks more like a stick or rod.
  • Female Guppy: The female guppy’s anal fin is fan-shaped and larger, resembling a triangle.

Size and Body Shape

  • Male Guppy: Males are generally smaller and more slender than females. They have a streamlined body shape.
  • Female Guppy: Females are usually larger and have a rounder, more robust body shape.


  • Male Guppy: Males tend to have more vibrant and colorful patterns and markings. They often display a wide range of colors and may have brightly colored tails and fins.
  • Female Guppy: Females are typically less colorful and may have more subdued or camouflaged patterns to help them avoid predators.


  • Male Guppy: Males are usually more active and display courtship behavior, such as chasing and showing off their finnage to females.
  • Female Guppy: Females tend to be less active and may show signs of pregnancy, such as a swollen abdomen if they are pregnant.

Gravid Spot

  • Female Guppy: One noticeable feature in pregnant (gravid) female guppies is a dark spot near their anal fin, which indicates the presence of developing embryos.

Mating and Reproduction

  • Males are the ones with the gonopodium and actively pursue females for mating.
  • Females give birth to live fry, and they can store sperm for several months, allowing them to have multiple batches of fry without mating again.

Observing these characteristics can help you determine the gender of guppies. If you are uncertain, observing their behavior during mating or looking for the presence of the gonopodium or gravid spot is a reliable method to identify male and female guppies.

Guppy Care and Aquarium Setup

Guppies are popular and beautiful aquarium fish known for their vibrant colors and relatively easy care requirements. To ensure their well-being and longevity, it’s essential to provide them with the right environment. In this section, we’ll cover the ideal tank conditions, water parameters, and other care requirements for guppies.

  • Tank Size: Guppies are small fish, but they are quite active and social. It’s recommended to keep them in a tank with a minimum size of 10 gallons (about 40 liters) for a small group of guppies. Larger tanks offer more stability and space for guppies to swim and interact, reducing territorial disputes and stress.
  • Water Temperature: Guppies are tropical fish and thrive in water temperatures between 75°F to 82°F (24°C to 28°C). Maintaining a stable temperature is crucial, so consider using a reliable aquarium heater, especially if your room temperature fluctuates.
  • Water Parameters: Guppies prefer slightly alkaline water with a pH range of 6.8 to 7.8.
  • Ammonia and Nitrites: Guppies are sensitive to ammonia and nitrites, so it’s crucial to establish a cycled aquarium. Regular water testing and water changes are essential to maintain good water quality.
  • Filtration: A quality aquarium filter is necessary to keep the water clean and maintain good water parameters. Choose a filter that can handle the size of your tank and consider a filter with a gentle flow as guppies are not strong swimmers and excessive water movement may stress them.
  • Tank Mates: Guppies are generally peaceful and can coexist with a variety of other fish. Ideal tank mates include other community fish like mollies, platies, tetras, and peaceful bottom-dwellers like Corydoras catfish. Avoid keeping them with aggressive or fin-nipping species, as guppy fins can be attractive targets.
  • Decor and Plants: Guppies appreciate a well-decorated tank with live or artificial plants. Plants provide hiding spots, reduce stress, and contribute to water quality. Floating plants can also help diffuse light and provide shade, which guppies may appreciate.
  • Lighting: Guppies don’t have specific lighting requirements, but it’s essential to provide a regular day-night cycle. Aim for 8-12 hours of light per day, and consider using a timer to maintain consistency.
  • Feeding: Guppies are omnivorous and will accept a variety of foods. A balanced diet can include high-quality flake or pellet food as a staple, supplemented with live or frozen foods like brine shrimp, daphnia, and bloodworms.
  • Water Changes: Regular water changes, typically 20-30% of the tank volume every 1-2 weeks, help maintain water quality and reduce the buildup of toxins.

By creating a suitable habitat and following these care guidelines, you can enjoy the beauty and activity of guppies in your aquarium. Always monitor your guppies for any signs of stress or illness and be prepared to address any issues promptly to keep your fish healthy and happy.

How To Tell If a Guppy Is Male or Female? - "Guppy coppia gialla" by Marrabbio2 is licensed under CC BY-SA 3.0.
How To Tell If a Guppy Is Male or Female? – “Guppy coppia gialla” by Marrabbio2 is licensed under CC BY-SA 3.0.


Breeding guppies can be a rewarding and educational experience for aquarium enthusiasts. Part of this is knowing how to tell if a guppy is male or female. These colorful fish are known for their prolific breeding habits. In this section, we will explore the basics of guppy breeding, including setting up a breeding tank, understanding breeding behaviors, and caring for guppy fry (baby guppies).

Setting Up a Breeding Tank

  • Separate Breeding Tank: It’s recommended to set up a separate breeding tank, typically a smaller aquarium, to isolate the breeding pair and their fry from potential threats in the main tank.
  • Tank Size: A 10 to 20-gallon (38-76 liters) tank is sufficient for breeding guppies.
  • Filtration: Use a gentle filter to prevent fry from being sucked into the filter. Sponge filters work well for this purpose.
  • Heating: Maintain a stable temperature between 75°F to 82°F (24°C to 28°C) using an aquarium heater.
  • Substrate and Decor: Add live or artificial plants for cover, which provides hiding spots for the fry. Marbles or a breeding trap can be used to separate the fry from adult guppies.

Breeding Behaviors

  • Selecting Breeding Pair: Choose healthy, mature guppies for breeding. Males should have well-developed gonopodiums, and females should be in good condition.
  • Courtship: Male guppies exhibit courtship behavior by chasing and showing off their colorful fins to females. This display is known as the “mating dance.”
  • Mating: When a female is receptive, the male will transfer sperm to her through his gonopodium. Females store sperm, allowing multiple pregnancies from a single mating.
  • Pregnancy: Guppy pregnancies last around 26-31 days. A gravid spot near the female’s anal fin darkens as the pregnancy progresses.
  • Isolation: After mating, you can move the pregnant female to the breeding tank or use a breeding trap in the main tank to protect her from harassment.

Caring for Guppy Fry

  • Hatching: Guppy fry are born live and fully formed. A female can give birth to 20-100 fry, depending on her age and condition.
  • Hiding Places: Fry are vulnerable to being eaten by adult guppies, so provide plenty of hiding places. Floating plants or a separate breeding trap can help protect them.
  • Feeding: Initially, feed the fry with powdered or liquid fry food. As they grow, transition to finely crushed flake food and small live or frozen foods like baby brine shrimp or micro worms.
  • Water Quality: Maintain excellent water quality with regular small water changes, as fry are sensitive to changes in water parameters.
  • Growth: Guppy fry grow quickly, and you can move them to the main tank when they are large enough to avoid being eaten by adult fish, usually around 4-8 weeks old.

Breeding guppies can be a fascinating hobby, and with proper care and attention to the needs of both adults and fry, you can successfully breed and raise these colorful and vibrant fish in your aquarium. Always observe the well-being of your guppies and be prepared to make adjustments as needed to ensure their health and safety.


In the world of aquarium keeping, guppies stand out as captivating creatures that bring life, color, and joy to our tanks. Knowing how to tell if a guppy is male or female is just the first step in understanding and caring for these lovely fish. From setting up an ideal habitat to fostering the joys of breeding and nurturing guppy fry, the journey of guppy ownership is filled with wonder and discovery.

As you delve into the intricacies of guppy care, you’ll find that observing their behavior, tending to their needs, and even witnessing the birth of their fry can be a deeply rewarding experience. Guppy enthusiasts know that the world of these small, vibrant fish is a universe in itself, where beauty and intrigue coexist. With the knowledge and insights gained from this article, you’re well-prepared to provide the best care, appreciate their unique personalities, and become a skilled guppy breeder. So, whether you’re a beginner taking your first plunge into the aquatic realm or a seasoned aquarist seeking to expand your horizons, the world of guppies offers endless opportunities for learning and enjoyment.