Pregnant Guppies: Vanishing Act?

Guppies are live-bearing fish, which means they don't lay eggs but instead give birth to free-swimming baby guppies. If you have a mixture of male and female guppies, you will likely end up with pregnant females. There are several signs that indicate a guppy is pregnant, including a bulging belly, a noticeable gravid spot, higher aggression, swimming in place, rapid breathing, and the presence of males in the tank. As the pregnancy progresses, the female guppy's belly will become larger and more box-shaped, and the gravid spot will become darker and more prominent. Pregnant guppies may also exhibit behavioural changes, such as increased aggression towards males and hiding behaviour as they seek a peaceful spot to give birth. It is important to provide proper care for pregnant guppies, including a well-balanced diet and optimal tank conditions, to ensure the health and growth of the fry.

Stress and poor water conditions

Reducing Stress

Pregnancy is a naturally stressful time for female guppies, and external factors can further elevate their stress levels. To minimise stress, it is crucial to provide good living conditions, ample space, and a nutritious diet. Aggressive tank mates can also increase stress levels, so choosing peaceful fish species as tank mates is essential.

It is important to monitor the guppy's behaviour for any signs of stress, such as low energy, erratic swimming, refusal to eat, or swimming near the bottom of the tank. If these behaviours are observed, check the tank conditions and ensure that the water parameters, such as temperature and pH levels, are ideal for pregnant guppies.

Improving Water Conditions

Poor water conditions and irregular parameters can significantly impact the health of pregnant guppies. Water quality is crucial, and dirty or unfiltered water can increase stress levels. Quick changes in water parameters should be avoided, as guppies may struggle to adapt to sudden shifts in their environment.

To maintain optimal water conditions, regular water changes are recommended, along with proper filtration to remove waste from the tank. Additionally, a heater can help maintain stable water temperatures, which is essential for pregnant guppies.

Using Breeding Boxes

Breeding boxes can be beneficial for separating pregnant guppies from other fish in the tank, but they can also be stressful for the fish if used for extended periods. It is recommended to only use breeding boxes when necessary and for short durations to minimise stress on the pregnant guppy.

Providing Hiding Places

Adding hiding spots, such as plants, to the main tank can offer protection for newborn guppies. Floating plants with roots can be especially useful for this purpose, providing a place for the fry to hide and reducing their chances of being eaten by other fish in the tank.

Hiding places and calmer environments

Provide Hiding Places:

• Live plants: Live plants, such as Java Fern, Java Moss, Guppy Grass, and Anubis, are excellent for providing hiding places for pregnant guppies. They also serve as a food source for the baby guppies, as they graze on microorganisms that live on the leaves.
• Decorations: In addition to live plants, ornaments and caves can also provide hiding places for pregnant guppies. Rocks, artificial plants, and other decorations can be used to create hiding spots.
• Breeder boxes: Breeder boxes or net breeders can be used to isolate pregnant guppies from other fish. These boxes have a separate chamber that the baby guppies can swim through, while keeping them safe from hungry adults. However, some guppies may find these boxes stressful, so it is important to provide other hiding options as well.

Create a Calmer Environment:

• Water parameters: Keeping the water parameters stable and optimal is crucial for reducing stress in pregnant guppies. Maintain the water temperature between 76°F and 80°F, and keep the amount of ammonia and nitrite at 0.
• Water flow: As baby guppies are not strong swimmers, use a filter that creates low water movement in the tank. A sponge filter is a good option.
• Tank setup: A ten-gallon or larger tank is ideal for pregnant guppies. While guppies can be kept in a bare-bottom tank, providing a substrate can make them feel more comfortable. Just be sure to use a lid/hood to prevent them from jumping out.
• Filtration: Protect baby guppies from being sucked into power filters by placing a prefilter sponge or tights over the filter's intake.
• Water changes: Regular water changes, such as a 25% weekly water change, are important to maintain good water quality and reduce stress on pregnant guppies.
• Diet: Feed pregnant guppies a well-balanced and nutritious diet, including fish flakes, frozen brine shrimp, and small amounts of blanched vegetables. However, they may eat less as they get closer to giving birth.
• Tank mates: Keep aggressive tank mates separate from pregnant guppies, as they can be a source of stress. It is also important to separate males from females to prevent constant mating attempts, which can stress out the females.

Diet and nutrition

Pregnant guppies require a well-balanced and nutritious diet to ensure the health and growth of the fry. Guppies are omnivorous, so it is important to feed them a variety of foods, including fish flakes, frozen brine shrimp, and small amounts of blanched vegetables. It is recommended to alternate their diet every day between regular flake food, tiny fish food pellets, algae discs, krill, bloodworms, or brine shrimp.

During pregnancy, the female guppy's belly will get larger, and her gravid spot will become more prominent and darker. As the pregnancy progresses, it is essential to continue providing a nutritious diet to support the developing fry.

Once the guppy has given birth, the mother can produce a new brood after about a month without mating with a male guppy again, as she can store sperm for several months. However, it is important to note that guppies can get pregnant quickly after giving birth, and regular breeding can result in multiple batches of babies over a few months.

The baby guppies, or fry, are born ready to fend for themselves. They can eat larger foods right after birth, and the best food to feed them is baby brine shrimp, which is high in protein and fat. It is recommended to prepare a batch of baby brine shrimp just before the mother gives birth.

In addition to baby brine shrimp, the fry can also feed on powdered fish flakes and forage for themselves on microorganisms growing on live plants in the tank. Guppy grass and Java moss are excellent plants to have in the tank, as they provide coverage and security for the fry while also serving as a food source.

It is important to note that guppies can have a new batch of babies every month, so ensuring a well-balanced diet for the mother guppy is crucial to maintain her health and the health of the developing fry.

Water temperature

The ideal water temperature for pregnant guppies is between 75°F and 80°F (24-27°C). Guppies can survive in a wide range of temperatures, but water that is too cold will slow their metabolism, making them sluggish and reducing their appetite. Conversely, water that is too hot will cause hyperactivity, leading to stress, and can create an oxygen deficiency.

It is recommended to use a heater to maintain the perfect water temperature for pregnant guppies and their fry. A thermometer is also useful to monitor the actual temperature.

Gradual changes are important when adjusting water temperature, as abrupt shifts can induce stress in the fish.

Pregnant guppies are vulnerable, and stress can lead to a loss of appetite or even cause the female to absorb or miscarry her babies. Therefore, it is crucial to maintain stable and optimal water temperatures to support the health of pregnant guppies and the successful birth of their fry.

Breeding tanks and boxes

The use of a breeding box, also known as a breeder net, is a cost-effective and straightforward method to safeguard guppy fry. It is a small container placed inside the main tank to isolate pregnant females. The box allows water to flow freely in and out, providing oxygenated water for the fish. It is recommended to place the pregnant guppy in the breeding box when you notice signs of labour, such as erratic swimming or restlessness.

Ideally, the mother guppy should be removed from the breeding box within 24 to 48 hours after giving birth. However, she can be kept in the box longer if water conditions are optimal, with good water flow, clean water, and sufficient food. It is crucial to monitor the guppy for signs of stress and remove her if necessary.

Breeding tanks serve a similar purpose to breeding boxes but provide more space for the pregnant guppy and newborn fry. They are separate tanks that can be set up with the necessary equipment, such as a heater, gentle filter, appropriate lighting, and hiding spots. The water temperature should be maintained between 78 and 82 °F, and the water quality should be regularly monitored to ensure stable conditions.

It is important to note that keeping a pregnant guppy in a breeding box or a small bowl for an extended period (more than two weeks) can cause stress and potentially lead to death. Therefore, it is recommended to use these tools only when necessary and to provide optimal water conditions to reduce stress.

In addition to breeding boxes and tanks, alternative methods to protect guppy fry include the use of artificial or live plants and separate tanks for fry. These options provide hiding places for the fry and reduce the risk of cannibalism by adult guppies.

Frequently asked questions