Whether betta fish need an air pump depends on specific breeding conditions. Below is a comprehensive analysis:
1. Respiratory Characteristics of Betta Fish
Betta fish (including Siamese fighting fish and Chinese bettas) possess a labyrinth organ, which allows them to breathe air directly from the water's surface. This reduces their reliance on dissolved oxygen in the water. Experiments have shown that healthy bettas can survive in still water environments (such as a 3-liter small tank) without additional oxygenation.
2. Common Scenarios Where No Air Pump Is Needed
Solo Housing: A single betta in a small tank (≥3 liters) can meet its needs with regular water changes (1/3 of the water weekly).
Still Water Environments: Bettas prefer weak water flow. An air pump may cause stress, especially for Siamese fighting fish.
Low-Density Housing: If the tank has sufficient space (1 fish per liter of water), the dissolved oxygen level is usually adequate.
3. Special Scenarios Where an Air Pump Is Necessary
High-Density Community Tanks: If the tank is overcrowded (e.g., less than 2 liters of water per fish), additional oxygenation is required to maintain a dissolved oxygen level of ≥5mg/L.
High-Temperature Environments: When water temperature exceeds 28°C, the efficiency of bettas' skin respiration decreases, making oxygenation necessary.
Poor Water Quality: If ammonia nitrogen concentration exceeds 0.02mg/L or water changes are delayed, an air pump can assist in water purification.
Filtration System Compatibility: If using oxygen-driven filtration devices such as sponge filters, an air pump is needed to provide power.
4. Other Considerations
Species Differences: Chinese bettas tolerate low oxygen levels (4-6mg/L), while Siamese fighting fish require 3-5mg/L, and Plakat bettas have higher demands (5-7mg/L).
Water Flow Control: If using an air pump, it is recommended to reduce the bubble output (e.g., 1 bubble per second) to avoid strong water flow affecting the bettas' activity.
Conclusion
Bettas generally do not need an air pump under regular breeding conditions, but adjustments should be made based on factors like density, water temperature, and water quality. For ornamental purposes alone, still water plus regular water changes are sufficient. If filtration or special environments are required, an air pump can be used selectively.