If your betta fish isn't eating, here are the possible causes and solutions based on multiple reliable sources:
Common Causes and Corresponding Measures
Environmental Acclimation Period
Newly arrived bettas need 2-3 days of quiet adaptation. Avoid strong light and frequent water changes, and start feeding gradually once they’ve adjusted.
You can place them in a dark area (like a "little black room") to reduce external disturbances.
Abnormal Water Temperature
Betta fish are tropical fish, and the water temperature should be stably maintained above 20°C, with the optimal range being 25-28°C. Low temperatures can cause a loss of appetite, so it’s recommended to use a heater to keep the temperature constant.
When there’s a large temperature difference (such as day-night fluctuations), enhance insulation measures.
Water Quality Issues
High ammonia levels or unconditioned tap water may cause stress. You can temporarily use mineral water as a transition or add almond leaves to adjust the water quality.
Change the water regularly (1/3 of the water volume each time) and use a filter pump or "lazy leaves" to maintain stable water quality.
Inappropriate Food Choice
Bettas may refuse food that doesn’t suit their taste. It’s advisable to try live food (such as bloodworms, brine shrimp) or switch to a different brand.
When they’re sick, you can try mixing garlicin with their food to promote digestion and prevent enteritis.
Disease Factors
Enteritis/Internal Parasites: Symptoms include refusal to eat and bloating. You can use a metronidazole bath (add 4-6mg per liter of water) or a combined treatment of oxytetracycline and yellow powder.
Saprolegniasis/Ichthyophthiriasis: If there are fluffy substances or white spots on the body, raise the temperature to 30°C, add sea salt, and treat with methylene blue.
If white parasites are found, immediately change the water and disinfect the fish tank.
Handling of Special Situations
Refusal to Eat During Breeding Season: Male bettas may stop eating when courting. They need to be isolated, and red light can be used to interfere with hormone secretion.
Psychological Stress: Avoid sudden light or noise stimulation and keep the environment quiet.
Notes
Betta fish can survive without food for about 3 days. If they don’t eat for a long time, you need to check for the cause of the illness.
It’s recommended to stop feeding during treatment and gradually resume the feeding amount after recovery.
If the above methods don’t work, you can further check for potential factors such as dissolved oxygen and light. Hope your betta fish returns to health soon!