Guppy Fry Deaths: What's Wrong?

Guppy fry are delicate creatures that require careful attention to their living conditions. There are several reasons why your guppy fry might be dying, and it is essential to identify the underlying causes to prevent further losses. Here are some of the most common issues that lead to guppy fry mortality:

- Cannibalism: Guppy parents often show no interest in their offspring and may consume their newborns. Adult guppies pose a more significant danger to the fry than other fish species.

- Poor Water Conditions: Guppy fry are susceptible to high toxin concentrations and lack of oxygen in the water. Poor water quality can lead to diseases and compromise the health of the fry.

- Oxygen Deficiency: Guppies extract oxygen from the water through their gills. Insufficient oxygen levels can cause guppy fry to gasp for air and lead to their demise.

- Inadequate Feeding: Guppy fry require frequent feeding with appropriately sized food. Underfeeding or providing food that is too large for their mouths can result in starvation.

- Water Temperature: Guppies thrive in specific temperature ranges, and deviations can be detrimental. Extremely cold or hot water can be fatal, and drastic temperature swings can also be harmful.

- High Chlorine Concentrations: Tap water often contains chlorine, which is harmful to guppies and can decimate fry populations.

- Ammonia Levels: Ammonia is toxic to guppies, and even low levels can compromise their immune system or lead to direct fatalities.

- Overcrowding: Overcrowding can lead to oxygen deficiency and increased pollution in the tank, creating an unhealthy environment for guppy fry.

Poor water quality

To maintain good water quality, it is important to perform regular water changes, use a filter, and avoid overfeeding. It is also crucial to use a water conditioner to neutralize any chlorine or chloramine present in tap water. The optimal water conditions for guppy fry include a temperature of 78-82°F, and regular testing of water parameters such as ammonia, nitrite, nitrate, pH, and hardness is recommended.

In addition to maintaining water quality, providing hiding places for guppy fry is essential. This can be achieved by using live or artificial plants, such as java moss or hornwort, or adding rocks or driftwood to create caves and crevices.

Cannibalism

Guppies will mistake their fry for food and eat them if they are left in the same tank. This is a natural instinct that helps them survive in the wild, where food is scarce and predators are abundant. However, in a home aquarium, this behaviour can be detrimental to the guppy population.

To prevent cannibalism, it is essential to separate the fry from the adults as soon as possible. This can be done by using a breeding box or a net breeder to isolate the pregnant female before she gives birth. These devices allow water flow but prevent adult fish from reaching the fry. Alternatively, a separate tank can be used for breeding and raising guppy fry.

If fry are kept in the same tank as adults, providing plenty of hiding places is crucial. Live or artificial plants, such as java moss or hornwort, can offer dense cover for the fry. Rocks or driftwood can also create caves and crevices for them to hide from adult guppies.

• Regularly perform water changes of at least 20-30% once a week and use a water conditioner to neutralise chlorine and chloramine.
• Monitor water parameters such as pH, ammonia, nitrates, and nitrites, and maintain them within safe ranges.
• Provide a stable water temperature between 72-82 °F (22.2-27.8 °C).
• Feed guppy fry live food, such as bloodworms, daphnia, mosquito larvae, and baby brine shrimp, four to eight times a day in small quantities.
• Use a delicate air stone to increase oxygen levels and illuminate the tank for at least eight hours a day.
• Maintain a clean tank by removing dead plants, debris, and waste regularly.
• Avoid overcrowding in the tank, as it can lead to oxygen deficiency and increased waste production, negatively impacting the water quality.

Lack of oxygen

Guppy fry are very delicate and vulnerable to many threats, including a lack of oxygen in the water. Young guppies use their gills to extract oxygen from the water, and if there is an oxygen deficiency, they will die at a much faster rate than adult guppies because they are considerably weaker.

You should suspect a lack of oxygen if your guppies are constantly gasping for air at the surface of the tank. Guppies that do not have enough oxygen will also repeatedly open and close their mouths.

To prevent oxygen deficiency, avoid overcrowding your tank, as this can lead to oxygen deficiencies. If your tank is overcrowded, reduce the number of adult fish or get a bigger tank. You should also avoid turning off filters, as this can lead to oxygen depletion.

You can also add an air stone to create bubbles and increase oxygen diffusion, or add live plants, which produce oxygen during photosynthesis.

Poor nutrition

Guppy fry require more food than adult guppies, and they need to be fed several times a day. Poor nutrition is a common cause of guppy fry mortality. Guppy fry have small mouths, so their food must be appropriately sized.

Guppy fry should be fed live food such as bloodworms, daphnia, mosquito larvae, and baby brine shrimp. They can also be fed blanched vegetables like zucchini and cucumber to meet their plant-based nutritional requirements.

Fryers should be fed small amounts of food that they can finish within a few minutes. Any leftover food should be removed to avoid polluting the water.

• Feed them four to eight times a day.
• Feed them crushed flake food or pellets formulated for fry.
• As they grow older, introduce more variety into their diet.
• Feed them the same food as their adult parents, but make sure to crush it up first.

Inadequate water temperature

Guppies are tropical fish and require a specific water temperature to survive. If the water temperature is inadequate, guppy fry will die. Guppies prefer water temperatures between 72-82 °F (22-28 °C). Guppies can survive in water as low as 64 °F (18 °C), but the chances of diseases are very high. It is not recommended to keep guppies in water colder than 72 °F (22 °C).

Warmer water is also dangerous for guppies. As the water heats up, the oxygen level in the water lowers. In water with a temperature over 82 °F (28 °C), the oxygen level can be very low, and guppies can die due to suffocation.

If the temperature keeps changing drastically, swinging between hot and cold, the shock will kill your fry; they are too delicate to survive such stress. Guppy fry require consistency. To achieve this, it is highly recommended to use an aquarium heater to maintain a stable temperature.

Ideally, the temperature should be around 74 °F (23 °C). Do not allow wild swings to occur. Stability plays a significant role in keeping your guppy fry healthy. If you perform water changes, make sure that the water you pour is within the desired range.

Frequently asked questions