Why is my betta (Siamese fighting fish) not eating?

Check water first

Ammonia or nitrite in the water stresses fish and kills appetite. Test your water — if either is above zero, do a water change and fix the cause (overfeeding, overstocking, or an incomplete cycle). Bettas also need warm water (76–82 °F); a cold or fluctuating tank can make them lethargic and off food. Log parameters in App-aquatic so you spot problems early.

Stress and environment

New tank, new fish, or aggressive tank mates can make a betta hide and refuse food. Give them cover and quiet. If you added new fish or moved the tank, give it a few days and offer food in small amounts. Strong current can stress long-finned bettas; baffle the filter if the flow is heavy.

Food and routine

Some bettas are picky. Try a different pellet size or brand, or offer frozen/thawed bloodworms or brine shrimp as a treat. Soak pellets briefly so they sink slowly. Don’t overfeed to “make up” — one or two small meals a day is enough. Remove uneaten food so it doesn’t rot.

When to worry

If water is good, temperature is stable, and the betta still won’t eat for more than a few days, look for other signs: clamped fins, bloating, spots, or listlessness. See our fish illnesses guide and consider a hospital tank if you need to treat. Sometimes a short fast (24–48 hours) then a small, tempting meal is enough to reset.

Quick takeaways

• Test water (ammonia, nitrite); ensure temp is 76–82 °F. Fix water quality first.
• Reduce stress: cover, calm tank mates, gentle flow.
• Try different food or a short fast; don’t overfeed. If it goes on for days with other symptoms, consider illness.