11 Reasons Why a Betta Fish Lays at the Bottom of the Tank

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Betta fish owners will witness all kinds of weird behavior.

Still, a betta that’s laying on the bottom of the tank does sound alarming.

Is the fish turned on one side or are its fins supporting its body?

Is that a symptom of a serious illness or just another odd trait of character?

Will it be okay eventually or is that the final straw?

Why does it look as if your betta is breathing heavily?

Is it suffocating?

Let me explain.

A healthy betta needs its personal space, frequent water changes, and a properly diversified diet.

For the fish to prefer to stand still in an unnatural pose could mean a number of things.

Let me expand on those.

Figuring out why your betta fish lays on its side at the base of the aquarium

I can’t help but find the Betta one of the most weirdly-mannered fish I have ever kept. As they enjoy their privacy, In many cases putting a couple of aquatic plants will take care of the issue, but not always. Here’s why a Betta fish may lay on its side at the bottom of its tank:

A Betta fish may be resting on the bottom of its tank due to polluted aquarium water. Foul water conditions can make the fish lethargic due to the stress and in the worst-case scenario – poison the creature. Another common reason for a Betta that doesn’t move from the bottom would be a filter current that’s too strong for the fish to swim comfortably.

Regularly testing the water for the build-up of lethal Ammonia or Nitrite, and performing weekly aquarium maintenance can be a reliable way to keep a fish tank clean.

Note that this behavior is not always the result of something bad happening in the fish tank.

Here are the details:

1. It may be sleeping.

Betta fish, like most other animals, do need rest and will sleep. The fish will often find a comfortable place on the bottom of the aquarium where it will lay and take a nap during the night.

Sometimes a betta will snooze on a big leaf, closer to the top of the tank, as that’s where they do it in the wild.

Betta fish are not nocturnal, so their sleeping habits dictate being active during the daytime and going to sleep at night, or when the room gets dark.

They may also sleep in portions of about 1 hour at a time, multiple times a night.

Betta fish like to sleep lying on their side. It’s an interesting trait of theirs adding to their popularity among fishkeepers.

If your pet friend appears otherwise healthy and active, it is probably just taking a nap on the bottom.

Fun fact: There are even “betta beds” that represent artificial leaves, large enough to support a resting betta. Chewy, the reputable online store for pet supplies, has them in under 4 bucks. On that note, Amazon does too.

Anyway, if you’re like me (amused at how absurd it looks) then you’d be happy to give your pet a comfy bed.

The leaf should be mounted at the top of the tank.

Closer to the surface is where Betta fish spend their time in the wild.

Caution: Don’t mistake sleep with exhaustion. A betta will go to sleep whenever the lights are off.

Keeping them on constantly can confuse the fish. It will swim around until it’s exhausted and then have a prolonged rest somewhere in the tank.

Exhaustion can weaken your betta’s immune system.

2. It has Nitrate poisoning.

Long-term exposure to Nitrate is one of the if not, the most common reason behind a Betta fish that’s lethargically lying on the bottom of its aquarium.

Is your Betta fish also progressively losing its coloration and beginning to look pale?

Is it lacking appetite?

Do its gills move rapidly as if the fish is out of breath?

If you notice a combination of these signs then it’s very likely that your Betta spends its time on the tank’s bottom because it has been poisoned by the Nitrate content in its aquarium water.

If you click the link you’ll learn everything about that condition and how to immediately treat it, but I’ll give you a quick rundown.

Prolonged exposure to even 20 ppm (parts per million) of Nitrate will sooner or later cause signs of illness.

You’ll hear most aquarists say that anything between 20 and 40 ppm is safe to have in a freshwater aquarium.

This, however, is a common misunderstanding that originated from the fact that nitrate is relatively less harmful when compared to nitrite and ammonia.

Both ammonia and nitrite are extremely toxic to aquarium fish, where nitrate is more of a silent, slow killer.

Arm yourself with a reliable liquid test kit and perform a water test. Test strips can only give a rough estimation of the situation but are nowhere near accurate.

In the case of poisoning, you’d need to know exactly how much Nitrate is there in the Betta fish tank.

This is so because you’ll need to calculate how much water you’ll need to remove.

A good water test to precisely measure the Nitrate in an aquarium would be the API Master test kit (this link leads to Chewy.com).

You’ll now need to physically remove the Nitrate through water changes but do so in a slow and controlled manner. Changing too much aqurium at once may cause shock to your Betta fish.

3. It’s lazy.

Sometimes, it’s not a lack of sleep but rather a lack of motivation.

If the front pelvic fins are moving and supporting a Betta that’s sitting on the bottom of its tank, then the fish is most likely being lazy.

Being lazy is a common trait of ornamental Betta fish.

Having huge fins is not always fun for swimming, so the fish eventually develops a habit of chilling at random places in the aquarium, and more often than not, this happens to be the bottom.

Monitor the behavior of your fish.

If your Betta moves around and feeds normally in-between “rests” then there’s nothing you should worry about.

Anyway, getting one of the Betta hammocks I mentioned above will provide your fish with its own resting space, away from the bottom.

4. It has a malfunctioning Swim Bladder.

Another reason for a Betta to remain on the bottom or even swim sideways may be the swim bladder disorder (click the link to check the extensive guide I wrote on that).

The Betta fish’s swim bladder is narrowed due to overfeeding or constipation, among other reasons.

The stomach swells, hindering the swim bladder’s proper functioning.

The condition is not lethal in its nature but it makes swimming really hard for the fish.

Sometimes a Swim Bladder malfunction causes Betta fish to spend a lot of their time laying around the bottom, as they find it difficult to move.

They may also float uncontrollably to the top, but still turned sideways or even upside-down.

The disease can be treated by fasting the fish and feeding it foods that contain more fiber.

An approach I find extremely effective is to feed the betta a crushed pea or some Daphnia, which are both an excellent source of fiber.

For the former – peel the pea and boil it before the offering. You should fast the fish for at least 1 day (24+ hours) after that.

Be sure to clean the tank of pea leftovers, as cooked peas can make a mess in the aquarium’s water.

Using Daphnia is pretty straightforward and the preferred choice among aquarists.

Personally, I also prefer to feed my Betta some Daphnia as it is a natural source of fiber for this fish. Betta fish are carnivorous and that’s what they would eat if they were in the wild.

To avoid constipation and, consequently, Swim Bladder malfunctions I can recommend feeding your Betta with high-fiber food at least twice a week.

The other type of bloating in Betta fish can be avoided if you soak any pellets for 2 to 3 minutes or so before feeding them to your fish.

This allows the food to swell outside of my fish’s stomach.

Don’t forget you need to soak them in aquarium water, or at least one that has been dechlorinated.

For extra constipation-prevention diversify your Betta’s menu by feeding it bloodworm (a type of water flea larvae) occasionally.

Bloodworms are another food that replicates the natural diet of a Betta fish. An organic diet may help the fish in fighting off disease and it can also make its bright colors stand out more.

5. Filter current is too fast.

Some may argue that Bettas don’t really need a filter because the fish can get tired quickly if the output current is too strong for its oversized fins.

Though the part about Betta fish not needing a filter is wrong, it’s definitely recommended to go for a sponge filtration in smaller fish tanks of 5 or fewer gallons.

That’s unless your aquarium kit comes with a built-in filter, which usually isn’t too strong.

Most selectively bred Betta fish have massive fins that make swimming in more turbulent water difficult.

So if your Betta seems less active and prefers to relax on the bottom of its tank, try tuning down the filter’s water circulation.

Not every filter has a flow-controlling valve, but many do.

My success for a 10-gallon single Betta tank has been with this such one filter (link to view it on Chewy) which has the adjustable flow feature.

Being able to control the flow in a small tank has made my pet friend twice as active.

For small fish tanks that hold between 3 and 5 gallons of water, you can likely get away with using a cheap sponge filter such as this one (make sure to get the “Mini”).

For my larger tanks that include a betta or other community fish with large fins, however, I am quite satisfied with using the AquaClear Power Filter 50. Chewy has those as well.

In my opinion, that last one crushes the competition on price tags that come with the same functionalities.

Both HOB filters work pretty well with my super poly-fil hack, by the way (link goes to my article on that).

Anyway, if you can’t get a filter with an adjustable flow rate right now, there are several DIY approaches you can try:

  • Strap a bio bag or any other kind of filter media on your filter’s water outlet. You can use a rubber band, fishing line or a cable zip tie to secure its placement.
  • Disperse the flow from the filter. Although you can get awfully creative here, I can confirm two easy and efficient ways to do that:

    – Tank divider kits are super cheap and will provide you with the perfect flow baffle and the means to attach it. Mount the mesh in front of the flow outlet.

    – Use a brand new plastic soap dish. Soap can be toxic to fish, so go and get a new cheap one from Walmart. They usually come with holes that are perfect for spreading the flow of your filter. Of course, go for the ones with suction cups.

  • Block the flow with plants or decoration. A well-planted tank will provide a safe place for your betta, away from the mean filter flow. You can also block the current with rockwork or artificial caves.
  • Drill holes in the intake pipe of your filter. This is simple physics. More holes or a larger intake pipe will reduce the pressure and therefore slow down the flowing current.

Note: It has been the case that I get asked if Betta fish need a filtering system quite often (more than I would like to admit). Betta fish produce waste and do need filtration.

Canister filters still hold the #1 place when it comes to maintaining decent water conditions.

If you’re planning on getting one, use a spray bar as an outlet.

These filters provide a strong flow rate, which needs to be spread out when dealing with long-finned fish.

Browse some options and mind that you should not use them in aquariums with less volume than 10 US gallons.

6. Water is too cold.

Naturally, as with any other cold-blooded creature, a Betta won’t tolerate cold water.

They are tropical and thrive in waters with a temperature of 75 to 82 degrees Fahrenheit (24 to 28 in Celcius).

If the water is too cold, your betta’s metabolism will gradually slow down.

This will cause the fish to become lethargic and spend a lot of time at the bottom of your aquarium.

Slowly raise the temperature if you think this may be the problem.

If by any chance the aquarium does not have a heater do some quick research on the best heaters for tanks that hold between 3 and 10 gallons of water and get one as soon as possible.

7. Its water too hot.

In summer an aquarium can get really hot.

Warm water releases oxygen too quickly which may leave your Betta gasping on the bottom.

Though Betta fish possess a special organ called Labyrinth, allowing them to breathe atmospheric air, they still may die if the water is poorly oxygenated.

In this case, you have to lower the temperature and add some extra oxygen to the tank:

  1. Lowering the temperature – DON’T use ice packs or ice cubes in the water.

    The sudden temperature change will stress both your pet fish and the beneficial bacteria in the aquarium and, perhaps, even kill them. What you can do is place a fan to blow directly on your aquarium’s water surface.

    Another (obvious) solution would be air-conditioning the room. You could also eliminate any direct sunlight reaching the aquarium.

    Don’t keep the fish tank lights on for over 6 hours, which should be more than enough for your aquatic plants to grow. Note that LED lights emit little to no heat, so get one of those if you have the chance (hint: the link will help you with that).

  2. Oxygenating – Use a small air pump to help with bringing more oxygen to the fish tank (Chewy.com has some durable ones for under $10).

8. Old Age.

Betta fish can live a happy and healthy life for about 4 to 5 years with good care.

Some may live even longer, but after hitting the 5-year mark they will become lethargic and more susceptible to disease.

Older Betta fish won’t have that youngster energy to explore. They will prefer laying around on leaves or the bottom of your fish tank.

Leave the elderly to peacefully reflect on their past.

9. High ammonia levels.

If your betta seems as if it’s gulping intensively while laying on the bottom then the fish tank may have an ammonia issue.

Ammonia spikes can be quite deadly to aquarium fish, so you need to confirm this as soon as possible.

Confirming an Ammonia poisoning is really simple – test your fish tank’s water. An excellent way to consistently monitor the ammonia in a fish tank is using Seachem’s Ammonia Alert sensor. It accurately tracks ammonia levels continuously and it lasts for almost a year, which is impressive, given that it only costs around $7.

Finding the roots of the problem, however, can be more complex. A couple of reasons for high ammonia may be:

  • An overstocked tank – the fish produce too much waste for the beneficial bacteria to handle.
  • Overfeeding – again, food waste turns into Ammonia.

    Monitor how much your betta actually consumes and offer less food than it can eat in one feeding session.

    Good prevention of overfeeding is getting an automatic feeder.

    It will feed the fish just the right amount, even when you’re out of town.

    I can recommend this one on Chewy, as it’s an Eheim and it seems to work consistently.

  • Incomplete tank cycling – you’ve added the Betta before the aquarium was ready to harbour live fish.

    Tank cycling is when you leave the beneficial bacteria enough time to develop a colony. In return, they will transform the dangerous ammonia levels to the way less harmful Nitrates.

    A fully cycled fish tank shows readings of 0 ppm of Ammonia, 0 ppm of Nitrite, and 10 or more ppm of Nitrate.

    Full natural cycling takes no less than a month.

    You can speed that process up to just about 2 weeks if you’re using bottled bacteria to kick start the Nitrogen cycle (learn more about that by clicking the link to see the guide I wrote).

The good news here is that you can almost always fix high ammonia levels by water changes.

Your initial water change should be no more than 50%.

Dechlorinate the new water before putting it in the tank by using a water conditioner such as Seachem’s Prime and continue to perform a 20% water change every week.

10. Stress or Disease.

There are a number of diseases that put a fish on the bottom of its tank.

Due to the way betta fish are bred their immune systems are weaker than most fishes’ by definition.

If you haven’t found the solution to your problem above in this article then I have bad news for you.

If hanging out at the bottom is combined with atypical behavior, loss of coloration, cloudy eyes, inflamed fin patches, etc. then your betta is probably sick and you should definitely be concerned.

All of these symptoms alert something more than a lazy personality.

If it’s a female betta with a swollen belly and you’ve concluded it’s not constipation then it may mean that the fish is eggbound.

Sometimes this condition sorts itself out, but not every time. If that’s the case, then little can be done.

Note that this is just one of the reasons for a bloat in Betta fish.

Anyway, if you suspect an infection then treating with Epsom salts can be beneficial.

You can also let some Indian Almond leaves sit in the water.

They will release tannins, which help with infections and strengthen the immune system of your fish.

Make sure your water parameters are in check.

A stress-free environment for your betta can also make the difference. One quick yet absurdly efficient way to reduce stress levels in betta tanks is by adding up some live plants.

These will artificially recreate the betta’s natural environment which may be a significant help in keeping stress at bay.

I recommend the addition of surface water plants that remain afloat if you think your betta may be stressed out. They filter the aquarium water from excessive organics, provide interesting surroundings for exploration and also get as close to the betta’s native rice paddies as possible. Oh, and they look great.

11. Its Aquarium is too small and the fish feels confined.

If you’re keeping your betta in anything under a 3-gallon tank, then it may be time for a change.

A 3-gallon tank is a BARE MINIMUM for a Betta fish. Ideally, you’d have yours in a 5 or 10-gallon tank.

An argument to upgrade would be that smaller tanks are very difficult to keep in check.

Each small change in the water’s parameters can immediately throw the whole system off balance and your will Betta have nowhere to retreat.

“Dilution is the solution to pollution.”

Anyway, another point I’d like to make is that, as mentioned above, Betta fish are curious, and also like their private space.

When the aquarium is too small and there’s no space to explore or retreat to the stress may start to show.

Your betta will lose its life spark and prefer to do nothing than staying on the bottom.

Remember that in their natural habitat betta fish have a ton of vertical space to swim in.

They are found in rice paddies and though shallow, these always provide more room to discover or a good hideout.

So, in case your betta tank is no more than 2-gallons in volume I would strongly suggest that you consider getting it a larger home.

Make sure the new place has LOTS of plants as well.

I can help with choosing the right aquarium with this guide.

Good luck.

The larger ones also give the opportunity to house more than just a betta.


To witness a betta peacefully laying at a fish tank’s bottom is not uncommon.

It’s all about knowing your fish and its habits.

Carefully monitor its behavior and conclude whether it’s just a way of living or an issue in disguise.

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82 thoughts on “11 Reasons Why a Betta Fish Lays at the Bottom of the Tank”

  1. I just received a new betta on Monday. He was in a cup. I set up a 20 gallon tank with a aqua-tech power filter 10-20 gallon and a tetra submersible heater 100 watts, with plants and hiding spots, floating logs…clean filtered water… the whole 9 yards. One of his little fins under him has curled and part of his tail has curled. He lays on the bottom of the tank and won’t eat. He has pooed. I’m concerned that the water still isn’t warm enough but I live out in the country so I ordered a thermometer which should be here by Saturday. While he rests his pectoral fins still move and he doesn’t seem to be breathing hard or anything. I’m not sure if he is just being lazy or if I should be concerned.

  2. Actually your right, I have a betta that I thought the reason why he always sit on the substrate is his body was accustomed to sitting in small cup that he can’t swim around so he just sits, but after a few months of having him I realized that his long fins and tail are the cause it’s dragging him down that it’s a lot of effort and energy to swim around so he decided to just swim if it’s feeding time or he got bored staring in one place. He’s feisty and active whenever he sees me so it means he’s just lazy for the reason I mentioned.

    • Hi,

      Yeah, that’s why it’s generally best to have nothing but a sponge filter in a Betta fish tank. Some breeders go over the top with the selective breeding… and it becomes very difficult for the Betta to swim properly with those enormous fins!

  3. I have a male betta, I don’t know for sure how old he is but he seems to be pretty old. He’s never been super active and has always enjoyed laying on his side but recently he hasn’t really moved from lying on his side whereas before he’d swim around a little. When he does swim he doesn’t seem to have trouble or be unbalanced, but he is only swimming a tiny bit, so it is hard to tell. He also hasn’t eaten much, maybe twice in the past week. Is this a problem or is it just another sign that he is getting older?

    • Hi A.,

      It may or may not be a sign of old age. The lack of appetite is not a good sign and can be caused by a plethora of conditions. Do you observe other signs of illness such as fading coloration, and rapid gill movement? Nitrate levels are within the healthy range for fish (no more than 10)? I would try to stimulate his appetite by adding a little bit of aquarium-grade garlic to his food. Garlic is a known appetite stimulant and may also boost his immune system to a degree. What do you usually feed him? Adding in some quality bloodworm or brine shrimp to his diet can also be beneficial. If he starts to eat on the regular and starts moving about the fish tank then you can consider your efforts a success.

      Hope this helps.

  4. Hi, my beta fish has been in the ground under one of my caves in the tank. He has been worrying me lately. We have had him around November 6th 2018. This started about one week ago. I cannot see him very well because it is too dark under the cave in the tank. He is in a 10 or 20 gallon tank and we clean the tank about once a week. He does not go up for food as much as he did before. We have not moved him Into a new tank at all.i do not know how long beta fish are supposed to live, we are afraid that he might be ill. We have been feeding him the same type of food, we have never tried to give him a different type of food. Do you think he cannot see the food and is just being lazy and not eating? Thank you please respond as soon as you can.

    • Hi,

      No, it is not that he’s being lazy if he doesn’t eat. Bettas live up to 5 years. Perhaps, there’s something wrong with his aquarium water, but with so little information I can’t be of help. What are the water parameters? Any recent changes to the fish tank? Is it bare bottom or it has live plants? Are you sure it’s “10 or 20 gallon” ?

  5. should I use rocks or gravel for the bottom of my Betts tank?

    • Hi Emma,

      No sharp objects (some rocks may be too sharp, but others would be fine), as the Betta’s fins can easily get hurt on those. Gravel is a sound choice, but if you plan on having some live aquatic plants, I’d recommend medium-grit sand.


  6. Hi,
    thank you for all these good answers.
    My beta is also glued to the bottom, but I could not find any matches for a disease.
    He was a very healthy 2-year-old male betta, living on a diet of only bloodworms, refusing any other food.
    Ammonia poising seems to be the most obvious, but he doesn’t show any signs.
    I already changed the water, he has a heater and a filter.
    Should I start an Ammonia block or add Fish salt?
    I am worried to stress him more than help.
    Thanks so much for your help!

    • Hi Nina,

      To check if you need to correct the wter’s parameters you first need to test them. What is your API Master test kit showing (don’t count on strips for precise data)?

      Don’t do too large water changes as this may also put stress on the little Betta. Do no more than 15 to 20% water change, but say, twice a week.

      Fish salt is always beneficial and reduces stress levels. It’s a temporary boost for their immune system, however, it could be enough of a kickstart for them to get back on track.

      Hope this helps


      • Thank you! I didn’t do a test yet, will get one at the pet store asap.
        He didn’t move all day and doesn’t do well.
        Color is still fine, just less strong, no bloating, no any other spots or signs.

        • It could be a long-term exposure to higher nitrate levels from what you’re describing.

  7. My betta is probably 2 or 3 years old. I have him in a 10 gallon aquarium. No lights, a heater and hang on the back filter. I typically do 50% water changes every 7-10 days. He has had a tank buddy, a panda Cory catfish who was with my previous betta fish. So the catfish was here before Junior. Recently, I went toPetco and bought 3 more cories, some aquarium live grass, he already had a mossy ball. There’s artificial grass, a bridge, a little white rock with holes, he has a floating log that he used to always spend his time in. Now, he spends all his time in the bottom, with the live grass. Part of me thinks he just loves the grass, the other is worried that he is ill. Would this be normal? Do they love grass this much?? He is not sideways, just hanging out down by the grass. Thank you. Worried in Missouri..

    • Hi,

      What are the water parameters? I suggest adding red root floaters (a species of floating aquarium plant) which will act as a nutrient sponge, sucking up excess nitrates (likely cause for lethargy) and also will create a more natural environment for the Betta. These plants do not need any form of care.

      Good luck, Xena

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