If your corydora fry are not eating, it's often a sign of stress, poor water quality, or issues with food availability. Addressing these factors promptly can significantly improve their chances of survival and growth.
Common Reasons Corydora Fry Stop Eating
Corydora fry are delicate and highly sensitive to their environment. Several factors can contribute to their refusal to eat:
1. Stress
Just like adult fish, corydora fry can go for a period without eating if they are stressed. A common source of stress is moving from one place to another, such as transferring them to a new tank or even significant changes within their existing habitat. Other stressors include:
- Overcrowding: Too many fry in a small space can lead to competition and stress.
- Aggressive tank mates: While less common with fry, any presence of larger or more active fish can intimidate them.
- Sudden changes in environment: Rapid shifts in lighting, tank decor, or the introduction of new equipment can be unsettling.
2. Poor Water Quality
Maintaining pristine water conditions is paramount for fry. Even slight deviations from optimal parameters can cause severe stress and lead to a loss of appetite. It's always a good practice to regularly check your water quality. Key parameters to monitor include:
- Ammonia, Nitrite, and Nitrate: High levels of these toxic compounds are a primary cause of stress and illness in fry. Ammonia and nitrite should always be zero.
- pH Levels: Ensuring your water's pH is within the good range for corydoras (typically neutral to slightly acidic, 6.5-7.5) is critical. Incorrect pH can be very stressful.
- Temperature: Stable and appropriate water temperature (around 74-78°F or 23-26°C) is vital for the fry's metabolism and overall health. Fluctuations can be detrimental.
- Water Hardness: While less common as a direct cause of not eating, extreme hardness or softness outside their ideal range can also contribute to stress.
3. Inappropriate Food or Feeding Practices
Even if food is present, fry might not eat if it's not suitable for them or if they can't access it.
- Food Size: Corydora fry have very small mouths and require micro-sized foods. Adult flakes or pellets are far too large.
- Food Type: They need highly nutritious foods designed for fry, such as infusoria, liquid fry food, powdered fry food, or newly hatched brine shrimp.
- Frequency and Availability: Fry need to eat very frequently throughout the day, often every 2-4 hours, as they have high metabolisms and small stomachs. Food should be constantly available in small quantities.
- Food Placement: Corydoras are bottom-dwellers. Food needs to sink to where they can find it easily without strong currents sweeping it away.
4. Developmental Stage
In the very first days after hatching, corydora fry may not eat because they are still absorbing their yolk sac. This yolk provides all the nutrition they need for the first 2-3 days. Once the yolk sac is fully absorbed, they will begin to actively search for external food sources.
5. Health Issues
Underlying health problems, such as bacterial infections, fungal infections, or parasites, can also lead to a loss of appetite. These are often secondary to poor water quality or stress.
Troubleshooting and Solutions
To help your corydora fry start eating, systematically address potential issues:
| Cause | Description | Solution |
|---|---|---|
| Stress | Recent move, overcrowding, aggressive tank mates, or sudden environmental changes. | Provide a stable, quiet environment. Avoid frequent disturbances. Ensure the tank is appropriately sized for the number of fry. Isolate fry from any potential threats. |
| Poor Water Quality | High ammonia/nitrite, incorrect pH, fluctuating temperatures, high nitrates. | Perform small, frequent water changes using dechlorinated, temperature-matched water. Test water parameters daily using a reliable aquarium test kit. Ensure pH and temperature are stable and within the optimal range for corydoras. Maintain excellent filtration suitable for a fry tank. |
| Inappropriate Food/Feeding | Food too large, not nutritious enough, insufficient feeding frequency, or food not reaching the fry. | Offer micro-sized foods like powdered fry food, newly hatched brine shrimp, or specialized liquid fry foods. Feed small amounts multiple times a day (4-6 times). Ensure food sinks and is spread across the bottom so all fry have access. |
| Yolk Sac Absorption | Fry not eating during their first few days due to reliance on the yolk sac. | This is normal. Begin offering food only after you observe the yolk sac has significantly diminished or disappeared (typically 2-3 days post-hatch). |
| Underlying Health Issues | Lethargy, visible spots, growths, or unusual swimming behavior, often secondary to stress or poor water. | Maintain optimal water quality as a first step, as good conditions aid recovery. Observe fry closely for signs of disease. Consult a veterinarian or experienced aquarist if symptoms persist or worsen. Avoid medicating fry unless absolutely necessary, as they are very sensitive to chemicals. |
By meticulously monitoring their environment and providing suitable nutrition, you can help your corydora fry thrive.
