Can Betta Fish Eat In The Dark? – Or Is It Dangerous?

betta fish eating

Are you afraid your Betta will be hungry during the night? It is a common worry every Betta-keeper has at first. Considering how hungry the fish looks all the time, it might be hard for them to stay hungry the whole night. If your thinking is in the same direction, you are absolutely wrong.

Betta fish can’t see properly in the dark. So, it makes no sense to give food when the fish won’t be able to locate it. Try to give food during the daytime or at least when the lights are ON.

The only way to keep a healthy and thriving Betta is to know its physical abilities and preferences. If you are comparatively new to Betta-keeping, this article is going to wash away all your questions regarding a night-time snack schedule for your pet. So, keep reading.

Key Takeaways

  • Due to having a small iris, Bettas can’t see properly without light.
  • It’s very difficult for a betta to navigate the whole tank in search of food in the dark.
  • Uneaten pellets or organic food can rot during the night and pollute the Betta tank.
  • Bettas are not a big of harsh lighting either. They prefer dimmed lights.

Can A Betta Fish Eat In The Dark?

Betta fish usually doesn’t eat in the dark. They depend on a circadian rhythm for their daily activities. It means the fish only likes to eat, hunt or explore under sufficient lighting. Once you turn the light OFF, the fish changes its activities. It tries to take rest or just relax.

That’s why you will hardly find your Betta enthusiastic to eat anything in the dark. Even if it’s their favorite food, they will try hard to stick with their daily routine. Apart from the “rhythm” or daily schedule, Bettas actually doesn’t see well without light. Unlike some gifted fish, they have rather poor eyesight in the dark. How is the betta going to find and eat food if it can’t even see properly? That makes sense, right?

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So, if you have a habit of giving food to your Betta during their “bedtime,” you are not helping them in any way.

Why Is It Not Okay To Feed A Betta In The Dark?

It is never a good idea to leave food for your fish while it’s sleeping. Here is list why you shouldn’t do so. Hope it helps.

1. Waste Of Pellets

You could have offered the pellets when the fish is actively searching for food. That’s when their appetite is at peak. Anything you give will be accepted immediately. However, Bettas finish most of their food within five minutes. After that, the remaining food becomes too soggy & might not appeal as much as before.

That’s why Betta-keepers remove any leftover food after 5 minutes. But if there’s no light, the fish won’t be able to locate let alone finish all the food within this time frame. Once the food starts smelling or degrading, even if your betta can see the food, it probably won’t touch it anymore. It will wait until the next meal comes. So, you have just wasted some pellets for nothing.

2. Risk Of Contamination

So what if the pellets are factory-produced? There are still biological ingredients. If the Betta fails to locate and eat every single pellet, the uneaten ones will rot. And the rotten food will soon produce harmful toxins in the tank. Imagine the poor fish surrounded by its own waste and leftover food.

If you have planned to clean the tank twice a week, that might not be sufficient anymore. A dirty tank like this needs to be cleaned immediately. The general rule for fish feeding is to remove any leftovers ASAP. After all, your main aim is to keep the Bettas in a germ-free tank.

white betta fish
Owner: SonicPavement

3. Extremely Hard To Eat Live Food

Want to feed some live insects to your fish? Bettas do enjoy bloodworms, mealworms and so on. But it will be extremely difficult for a Betta to track and hunt live food without proper lighting. Bettas can’t locate a prey, juts be smelling or hearing movement.

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4. Ruins The Sleep Cycle

Of course, it’s going to ruin the sleep cycle. Hunting an eating is an intensive job that requires lots of focus and energy. Nighttime is not ideal for that. Usually, the fish relaxes its nerves in the dark. Also, the metabolism starts to lower. All of this helps to create a perfect nap time. In the meantime, if the Betta somehow finds food, the entire concentration shifts to keep finding more food.

How Much Does A Betta See In The Dark?

Bettas have small and slow iris in their eyes. It works great during the day. Reportedly, Bettas can distinguish up to 300 colors if the object is close enough. Photoreceptors like cones are responsible for their clear vision under natural light. However, night vision depends on another kind of receptor called rods. When the “cones” fail due to the lack of light, rods kick in.

These photoreceptors can help you see objects even under extremely low lighting. Even though rods can’t detect colors as accurately as cones, it’s still workable. Unfortunately, bettas don’t have sufficient rods in their retina. Hence, they have a hard time figuring out the shape of an object after sunset.

In an aquarium, the case is slightly different. How much “dimmed” or dark the tank would be is under your control. So, you can choose to have low lighting instead of pitch-black darkness. We believe it’s better for the fish, as they can still navigate the tank if necessary. Don’t worry. You don’t have to buy a separate night light for the aquarium.

 If you don’t have one, just place the aquarium in a different direction. So that the light from other rooms indirectly hit the tank without being too loud. That will give the ‘subdued” vibe we were looking for. It is way better than “complete darkness.”

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However, for the nighttime, it’s better to go with colored lighting. Bright white light doesn’t imitate a sunset, no matter how dim it is. Instead, if you choose a blue light, it will recreate a moonlight vision underwater.

Owner: Lee McEwen

Will A Betta Fish Survive Without Any Aquarium Light?

Yes, staying in the dark isn’t life-threatening for a Betta. It will surely damage their sleeping and eating cycle. Luckily, it takes more than that to kill a Betta. Siamese fighting fish are known for being resilient. Especially in the wild, not every day is the same. Some days are cloudy and extremely dark. That means there will be inadequate light underwater for the fish to hunt and eat.

 Betta fish easily adapts to that situation by fasting and reducing daily activities. However, the darkness should not be extended more than one or two days. The fish can go under panic and start being lethargic. Bettas can fast for more than one week in case of emergencies. So, there is no need to pollute the tank with excess food by turning the aquarium lights OFF.

Under extended darkness, the fish will have a hard time eating until it’s full. The constant hunger will lead to malnutrition. Symptoms like weak bones and saggy and discolored skin will be easily noticeable. It’s a matter of time before the fish becomes extremely sick and die.

Before You Leave!!

An extended period of darkness is as harmful as excessive brightness. Don’t use harsh lighting during the nighttime. If you are worried the tank is too dark, try using dimmed lights with a blue hue. It imitates moonlight inside the tank and should provide a clear vision as well. Check out our article on “Does a betta fish like blue light at night?” Please read before making any decision.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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