Why Is My Betta Fish Not Eating? (7 Reasons + Fixes)

Your betta hasn’t touched his food in two days and you’re freaking out. I get it—when your fish suddenly stops eating, your mind goes straight to the worst-case scenario.

Here’s the thing: most of the time, a betta not eating isn’t a death sentence. It’s usually something simple like water temperature, stress, or just being a picky eater.

In this guide, I’ll walk you through the seven most common reasons why bettas stop eating and exactly what to do about each one. Plus, you’ll learn when it’s time to actually worry and call a vet.

How long can a betta go without eating?

Before we panic, let’s get one thing straight.

Healthy bettas can survive 10-14 days without food. Some bettas are even starved for 2+ weeks before being shipped to pet stores, so they’re tougher than you think.

That said, just because they can go that long doesn’t mean they should. If your betta hasn’t eaten in 5-7 days, it’s time to investigate and take action.

Ready to learn more about Betta? This post will give you fresh insights! Why a Weekly Fasting Day Helps Your Betta’s Digestion

Reason #1: Your betta is constipated (seriously)

This is the number one reason bettas stop eating, and most beginners don’t even think about it.

Your betta’s stomach is about the size of his eyeball. When you overfeed him, the food backs up in his digestive system and he literally gets too full to eat more.

How to tell if constipation is the problem

Look for these signs:

• Bloated, swollen belly (looks bigger than normal from the side)
• Stringy white poop hanging from his body
• Swimming around less than usual
• Spitting out food or ignoring it completely

How to fix it

Step 1: Stop feeding immediately. Give your betta 2-3 days with no food at all.

Want to know why in detail? Here’s the answer: Why a Weekly Fasting Day Helps Your Betta’s Digestion

This gives his digestive system time to clear out. Don’t worry—he won’t starve.

Step 2: After fasting, feed him daphnia or a tiny piece of blanched pea.

Daphnia acts like a natural laxative. You can find freeze-dried daphnia at most pet stores.

For the pea method, boil a frozen pea until soft, remove the skin, and offer a piece the size of his eyeball. Not all bettas will eat it, but it’s worth a shot.

Step 3: Going forward, feed less. Like, way less.

Most betta owners feed too much. Your betta only needs 2-3 pellets twice a day. That’s it.

Check this out: The 2-Minute Rule for Feeding Bettas (And How to Avoid Overfeeding)

Also, soak dry pellets in tank water for about a minute before feeding. Dry pellets expand in your betta’s stomach, which can cause bloating.

Reason #2: The water is too cold

Bettas are tropical fish from Southeast Asia. They need warm water.

When the temperature drops below 75°F, your betta’s metabolism slows down. His digestive system basically goes into low power mode, and he stops feeling hungry.

How to tell if temperature is the problem

Check your tank thermometer. If it’s below 75°F, that’s your answer.

You might also notice your betta is less active, hanging out at the bottom of the tank, or has clamped fins (fins held close to his body).

Hungry for knowledge about Betta? We’ve got you covered in this article. Should You Soak Betta Pellets Before Feeding?

How to fix it

Get a heater. Not optional—mandatory.

Set it to 78-80°F and keep it there. Once the water warms up, your betta should start eating again within a day or two.

Don’t do sudden temperature changes though. If your tank is cold, warm it up gradually over a few hours to avoid shocking your fish.

Reason #3: Poor water quality is making him sick

Dirty water is fish poison. Period.

When ammonia, nitrite, or nitrate levels get too high, your betta feels awful. Think about how you feel when you’re stuck in a stuffy, smelly room—you don’t want to eat either.

How to tell if water quality is the problem

Test your water with an API test kit (they’re like $25 and every betta owner needs one).

Here’s what you’re looking for:

• Ammonia: Should be 0 ppm
• Nitrite: Should be 0 ppm
• Nitrate: Should be under 20 ppm
• pH: 6.5-8.0 is fine for bettas

If any of these are off, especially ammonia or nitrite, your water is toxic.

How to fix it

Immediate fix: Do a 50% water change right now. Use a water conditioner to remove chlorine.

Long-term fix: Do 25% water changes every week. Get a filter if you don’t have one.

Also, stop overfeeding. Uneaten food rots and creates ammonia, which poisons your betta.

Reason #4: He’s stressed out

Bettas are way more sensitive than people think.

Stress kills their appetite fast. And there are tons of things that can stress out a betta.

Common stress triggers

• New tank or recently moved
• Aggressive tank mates
• Too much light (they need darkness at night)
• Tank is too small (5 gallons minimum)
• No hiding spots or plants
• Constant loud noises or vibrations

How to fix it

First, identify what’s causing the stress.

Did you just move him? Give him 3-5 days to adjust. New bettas often don’t eat for the first few days in a new home.

Are there other fish picking on him? Remove the bullies or give your betta more hiding spots with live or silk plants.

Is the light on 24/7? Turn it off at night. Bettas need a day/night cycle.

Bottom line: make your betta feel safe and he’ll start eating again.

Want to dive deeper into Betta? This article has all the answers! The 2-Minute Rule for Feeding Bettas (And How to Avoid Overfeeding)

Reason #5: He doesn’t like the food

Bettas can be picky little jerks.

If you switched foods recently, he might just refuse to eat because it tastes different or doesn’t look like food to him.

How to tell if food is the problem

Did you recently change brands or food types? That’s probably it.

Bettas are carnivores. They want meaty food that wiggles and looks alive. Boring pellets that sink to the bottom don’t always cut it.

How to fix it

Option 1: Mix in some high-value treats.

Try frozen or live bloodworms, brine shrimp, or daphnia. These are betta candy. Feed these a few times, then slowly mix in the pellets.

Option 2: Try a different pellet brand.

Some pellets are just bland or stale. Look for high-quality brands like Hikari Bio-Gold or Fluval Bug Bites. Make sure fish or shrimp meal is one of the first ingredients.

We have an in-depth guide on the best protein-rich betta food: What Is The Best High-Protein Food For Betta Fish? (Pellets, Frozen, Live)

Option 3: Check if your food is old.

Fish food expires. If your pellets are more than 6 months old, they might taste terrible. Toss them and buy fresh.

Also, never feed your betta tropical fish flakes. They can’t digest them properly.

Detailed answer here: Why Flakes Are a Bad Staple for Bettas?

Reason #6: He’s sick

If nothing else is working, illness might be the culprit.

Loss of appetite is one of the first signs that something is seriously wrong with your betta.

Common betta diseases that cause appetite loss

Swim bladder disorder: Your betta can’t swim upright, floats to the top, or sinks to the bottom. Often caused by constipation or injury.

Ich (white spot disease): Tiny white spots on fins and body, rubbing against objects. Treatable with medication.

Velvet: Gold or rusty dust on body, red streaks on fins. Needs copper-based medication.

Fin rot: Fins look ragged or melting. Usually from poor water quality.

Dropsy: Belly swells up, scales stick out like a pinecone. This is an emergency.

Discover more cool facts about Betta with this detailed post! Why Flakes Are a Bad Staple for Bettas?

How to fix it

For mild issues like swim bladder disorder from constipation, fasting and peas can help.

For parasites and infections, you’ll need medication. Check your local fish store for treatments specific to the disease.

If you see pinecone scales (dropsy), get help immediately. This is usually fatal unless caught super early.

Reason #7: Lack of oxygen in the water

This one doesn’t get talked about enough, but it matters.

Bettas have a labyrinth organ that lets them breathe air from the surface. But they still need dissolved oxygen in the water to stay healthy.

How to tell if oxygen is the problem

If your filter stopped working or you don’t have one, oxygen levels can drop.

You’ll notice your betta hanging at the surface constantly, gasping for air more than normal.

How to fix it

Get a filter. Even a gentle sponge filter helps circulate water and add oxygen.

Don’t put your betta in a tank with super fast water flow though—they hate strong currents.

If your filter stopped working, fix or replace it ASAP.

What NOT to do when your betta isn’t eating

Let’s talk about the mistakes that make things worse.

Don’t keep adding food hoping he’ll eat it. Uneaten food rots and creates ammonia. You’re poisoning your own fish.

Don’t immediately dump medications in the tank. Figure out the actual problem first. Random medications can stress your betta more.

Don’t put him in a tiny cup or bowl. Small containers have no stable temperature or water quality. Keep him in his main tank.

Don’t use Bettafix or Melafix. These can coat your betta’s labyrinth organ and suffocate him. Vets don’t recommend them.

Don’t panic and change everything at once. Make one change at a time so you can tell what actually worked.

When to see a vet (yes, fish vets exist)

Most of the time, you can fix a non-eating betta at home.

But sometimes you need professional help.

See a vet if:

• Your betta hasn’t eaten in 5-7 days despite trying fixes
• He has severe bloating with pinecone scales
• He’s lying on his side or can’t swim properly
• There are white spots, gold dust, or weird growths on his body
• He’s gasping constantly even with good water
• He’s getting visibly thinner

Look for a vet who specializes in fish or exotic pets. Yes, it might cost money, but it’s better than watching your betta suffer.

Want the inside track on Betta? This post is your go-to guide. What Is The Best High-Protein Food For Betta Fish? (Pellets, Frozen, Live)

How to prevent this from happening again

Once your betta is eating normally, keep it that way.

Feed the right amount: 2-3 pellets twice a day. That’s all he needs.

Fast once a week: Give your betta one day per week with no food. This prevents constipation and gives his digestive system a break.

Keep water pristine: Test weekly, do 25% water changes weekly, vacuum the gravel.

Maintain 78-80°F: Get a reliable heater and thermometer.

Feed variety: Mix up pellets, frozen bloodworms, brine shrimp, and daphnia. Keeps him interested and healthy.

Reduce stress: Provide hiding spots, keep the light cycle consistent, avoid aggressive tank mates.

Use a quarantine tank: When adding new fish or plants, quarantine them first to avoid introducing diseases.

Frequently asked questions

My betta spits out his food—is this normal?

Yes, sometimes. Bettas often grab food, spit it out, and grab it again.

But if he’s spitting out all his food and not eating any of it, the food might be too big or taste bad. Try smaller pellets or switch brands.

Check our in-depth guide on it: Why Your Betta Fish Spits Out Food (And How to Fix It)

Can bettas get bored of the same food?

Absolutely. They’re not robots.

If your betta suddenly stops eating pellets he used to love, try switching things up with treats like bloodworms or brine shrimp for a few days.

Should I use frozen or live food?

Both work great. Frozen is easier and safer (less risk of parasites). Live food is more exciting for bettas but harder to find.

Just avoid freeze-dried bloodworms as a staple—they can cause constipation. Soak them first if you do feed them.

My betta only eats bloodworms now—is that okay?

No. Bloodworms are treats, not a complete diet.

They’re like betta candy—high in protein but missing other nutrients. Feed them 2-3 times per week max, not every day.

How do I know if my betta is too thin?

Look at him from above. He should have a torpedo shape.

If he looks pinched behind the head or his belly is sunken in, he’s too thin and needs to eat more.

Final thoughts

A betta not eating is scary, but it’s usually fixable.

Start with the easy stuff—check the temperature, test your water, and try fasting for 2-3 days if you think he’s constipated. Most of the time, that solves it.

If nothing works after a week, don’t mess around. Get professional help.

Your betta depends on you to figure this out. With a little patience and the right fixes, he’ll be back to his hungry, feisty self in no time.