01/04/2026
*WHAT MAY CAUSE UNSUCCESSFUL HATCHING?*
In most cases, unsuccessful hatching has multiple causes from different angles, making it hard to detect and correct. Below are common issues that usually go wrong:
1. Broodstock of poor quality due to bad feeding, underfeeding, or being less than 12 months old.
2. The female does not release eggs. Possible reasons include low incubation water temperature (below 24°C), wrong dosage or expired hormones, poor handling and stress, or the female not being mature.
3. Stripped eggs showing many white eggs. This signals egg regression or off-season spawning. Catfish naturally spawn during the rainy season, so dry season eggs are often poor.
4. Eggs that look good but turn white within eight hours. This is often due to improper rinsing after tank disinfection. Even small chlorine traces can kill eggs quickly.
5. Delayed hatching when water temperature is 25°C or lower. Fertilisation to hatching may take 30 hours or more. The yolk-sac fry become sluggish, fail to swim to tank corners, and remain on the bottom where they risk bacterial or fungal infection. This reduces survival rates in the first two weeks of growth.
6. Poor water quality. Best results come with pH around 7, German hardness below 7, and iron content under 0.2mg/l. Catfish eggs hatch best in soft water. Hard water increases fungal growth, which heavily affects hatchlings.
7. Dirty storage tanks introducing bacteria into the system. Hatchery tanks should be cleaned at least every three months. Hard water (high in calcium and magnesium) causes rapid dirt build-up. Limescale on walls and pipes breeds bacteria, which reduces hatch and fry survival.
8. Low oxygen levels. If water does not flow constantly, oxygen drops. In flow-through systems, an aerator is strongly advised to maintain oxygen during incubation and fry growth.
