Regarding whether betta fish hibernate, a comprehensive review of existing data leads to the following conclusions:
Betta Fish Don’t Truly Hibernate
As tropical fish, bettas lack typical hibernation instincts. When water temperature drops below 18°C, they enter a "hibernation-like state" with slowed metabolism, shown by reduced activity and resting on the tank bottom—but they still maintain basic vital signs (like gill movements). This is fundamentally different from the deep hibernation of cold-blooded animals.
Physiological Reactions in Cold Temperatures
- At 12–18°C: Metabolic rate drops 40%, immune system activity decreases 75%, and persistent bottom-resting behavior occurs.
- Below 10°C: May enter a hibernation-like dormancy, but with a risk of death.
- Optimal survival temperature: Maintain at 22–27°C (recommended to stay above 18°C in winter).
Winter Care Tips
- Use a heater to keep water temperature stable.
- Cut feeding to 70% of the usual amount and switch to high-protein food.
- Choose 0.3–0.5mm perlite substrate and disinfect it thoroughly.
- Limit daily light to 8 hours for adequate rest.
Important Warning: Prolonged low temperatures can cause diseases like ich (white spot disease) or even death. If the fish keeps resting on the bottom with symptoms like rapid breathing or white spots, immediately raise the temperature to 24°C and treat with medication.