Betta Fish Laying On Bottom of Tank: Causes and Treatments

Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: June 7, 2024
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It can be quite concerning for any home aquarium enthusiast to notice their typically lively and healthy betta fish lying at the bottom of the tank.

While not always a cause for immediate major concern, it is definitely worth paying attention to.

If this is out of the normal realm of behavior for your fish in particular, it can be a sign of illness, distress, or poor water conditions and you may need to take action to prevent things from getting any worse.

If you’ve ever noticed your betta splendens laying on the bottom of the tank, or have wondered what to do if you see it, read on to find out the answer to this and many related betta issues!

Article Summary

  • Betta fish laying on the bottom of the tank is not always a cause for immediate concern but should be monitored.
  • Common reasons for betta fish lying on the bottom include stress, environmental factors, and health issues.
  • When a betta is lying on the bottom, monitor for additional symptoms, consult a qualified source, and follow medication directions as needed.

Some Quick Betta Background

Betta in a Fish Tank
Betta in a Fish Tank

Also known as Siamese Fighting Fish, the Betta splendens that many know and love has an undue reputation as an aggressive tropical fish.

Wild bettas were first found in the warm water of Thailand and eventually made their way to the domestic market in the mid-1920s with the explosive growth of hobby aquariums.


As members of the labyrinth fish family, bettas have adapted the ability to breathe atmospheric air thanks to the presence of a specialized organ. This came in handy with a betta laying on the dry surface after hopping from one rice paddy or puddle to another during dry seasons.

Fighting Fish

In reality, it is primarily the male betta fish that earns this reputation as a fighting fish, defending its territory with vigor and battling fish during breeding seasons.

Male bettas are quite the fin nippers, they have a tendency to fight with other betta males and will use both a display of fin and gill expansions and actual combat to get their way.

A fish with its fins nipped may have trouble swimming, and more dangerously may appear to be injured when actually sick with a disease such as fin rot.

Betta fish are adaptive, and hardy fish when it comes to the size of the tank and can tolerate conditions from a tiny bowl up to a larger tank system.


As a general rule, any pet fish suspected of disease such as fin rot or swim bladder disease should be immediately placed in a quarantine tank for observation.

Is It Normal For Betta Fish To Lay On The Bottom Of The Tank?

While not usually a regular betta fish behavior, sitting on the bottom doesn’t mean something is necessarily wrong! Consider conditions in your tank, and how your fish normally acts before jumping to any major conclusions regarding health.

Betta Sleep Hours

Betta fish need between 8 and 10 hours of sleep per night, and it’s important to create a consistently quiet, dark space for them to do so. Interrupting this sleep cycle can lead to increased stress, which in turn may mean your fish lays on the bottom of the tank.

Sleeping Betta Fish

One instance where they may more typically be seen on the bottom of the tank is when sleeping.

If you’re concerned about the appearance of your betta fish, make note of if this behavior is occurring during periods of darkness which may accidentally signal to your betta that it should be sleeping.

Why Is My Betta Fish Laying On The Bottom Of The Tank?

Betta Fish at Bottom of The Tank
Betta Fish at Bottom of The Tank


It may seem unusual to think of something like stress being an issue for something that appears as calm as a typical betta fish.

However, bettas are in fact quite sensitive to overstimulation.

While harmless at first, continued exposure to high stress levels can lead to illness, damage to the immune system, and even death.

One of the most common reasons to see any difference in the behavior of your betta fish is stress.

This may be caused by a variety of changes to the betta fish tank, such as the introduction of tank mates, stress from changing conditions or water specifications, shock from extra light, to being a recent new fish from the local pet store.


Signs of stress include seeing a lethargic fish, sitting at the bottom of the tank, and in some cases unusual behavior such as breathing heavily, swimming sideways, clamped fins sitting against their body, or moving towards the surface.


The key thing to keep in mind with stress is that it can be prevented.

Careful handling of your betta fish, along with close attention to the water condition, nutrition, and amount of stimulus your fish is exposed to goes a long way toward keeping your betta healthy and happy.

If you notice that a particular fish is stressed out, there are a few helpful things you can do.

Lowering the lights, removing any additional sources of loud noises, and potentially even moving the betta to its own separate tank can see a change in as little as a few hours to a few days, depending on severity.


Environmental factors play a huge role in the health of the betta fish. Bettas naturally live in warm and slightly acidic water. Providing a home that’s close to their natural environment is helpful to keeping them healthy.

Things like aquarium size, lighting, plants, and even substrate gravel all play a part in your betta’s own aquatic world and can determine how they feel and behave.

Too small of a fish tank or fish bowl can lead to your betta staying fairly stationary. Smaller tanks are also more prone to changes in water parameters.

We recommend a minimum of at least 5 gallons for one betta fish, with 5-10 gallons per additional fish after that.

Cramped Space

Betta Fish in Small Display Tank
Betta Fish in a Small Tank

A small space means that the betta fish will never truly feel comfortable or like they have enough room, which may mean they sit at the bottom of the tank.

In general, there is no such thing as too much swim space for a betta! When in doubt, choosing a bigger tank over a small one will lead to a happy healthy betta.

Regular cycles of lighting are critical to betta health. Like many other fish they require a consistent night and day in order to fall asleep, and moving away from this can make them stressed.

Using an aquarium timer attached to your fish tank lights is a great way to create a consistent sleep cycle for your betta while taking the pressure off of you to monitor this task yourself. 

Live Plants

Live plants are a great way to introduce oxygen to the tank, aid with tank cycling of nitrogen, and give your betta something else to interact with. Another option is a bubbler, it can help increase dissolved oxygen.

Betta fish love to explore plants, using them to hide in instances where they may feel threatened or have the need to make their own swim space.

Additional Filtration

Photo of an Internal Filter
Aquarium Filter

Being able to break up the line of sight can go a long way towards helping them establish a sense of safety and territory.

While betta fish can tolerate algae to a certain degree, if you start seeing the presence of excess plant material floating around your tank it’s usually a sign of poor quality tank water.

Look into increasing the filtration present in your betta tank, and consider a regular water change.


A well planted tank can also help ease the presence of having additional fish from causing stress or aggressive behaviors in your betta.

Water Parameters

Testing the quality of your water chemistry on a regular basis, monitoring temperature, and keeping an eye on the presence of excess sediment buildup are key components of preventing sick betta fish lying on the fish tank’s bottom. Sudden changes to the water parameters can also harm the beneficial bacteria in your tank.


Most pet stores sell testing kits that can help you look at factors such as pH, salinity, and ammonia levels.
Seeing floating bits of debris and algae filled water is a bad sign! Such conditions can end up causing disease to your betta, along with the high likelihood that there isn’t enough oxygen in the tank.

Aquarium Water Quality

Blue and Orange Betta
Blue and Orange Betta

Betta fish naturally produce waste as they eat and digest, which greatly affects the water quality.

More bettas and other tank mates means more waste, which can rapidly spiral to unhealthy levels and nitrate poisoning if your filtration system isn’t up to the task.

Proper Filtration

Make sure that you know the amount of filtration and water flow that you need for your new tank size and number of fish to prevent nitrate poisoning.

While the biological filter created by the beneficial bacteria in your tank can help, an extra air pump or sponge filter may be needed to increase water flow and move larger debris out of the tank. Good filtration also helps prevent ammonia poisoning or nitrate poisoning.


If you’ve found that your aquarium water is in danger of nitrate poisoning, the use of a commercial water conditioner can return conditions to a bearable level by nullifying the ammonia present in the tank.

Water Temperature

As a tropical warm water animal, bettas prefer water temperatures within the range of 75-80 degrees Fahrenheit.

While a few degrees above or below this range in betta tanks will not likely cause much harm, a rapid or larger shift in temperature can lead to temperature shock and cold water will see your betta acting stressed, slow, and sometimes not moving.


A shocked fish will show many of the same distress signals as a stressed person doused in ice cubes.

They may begin the process of partial hibernation if too cold, becoming lethargic as you see betta laying on the bottom of the tank.

Drastic Temperature Change

Too high of a water temperature can at first lead to a flurry of activity as the fish swims extra in preparation for the breeding season. After time, the fish will tire, leading to betta laying on the bottom of the tank.

If your tank winds up too cold, it’s best to slowly raise the temp to prevent potential temperature shock.


While it may seem insignificant, tank positioning can play a role in the water temperature of the tank, even for larger tanks. Sitting in direct sunlight can gradually raise the water temperature above what’s required for your betta, acting as a slow killer.

Ammonia Levels

Excess waste, an overstocked tank, decaying once-live food, and the presence of dead betta fish and plants can all raise the ammonia level in the tank.

Too much ammonia can be dangerous because it can damage the cells and tissues of bettas, a condition called ammonia poisoning.

With ammonia poisoning, you’ll see your fish present with clamped fins, betta fish hanging motionless and unable to move, and potentially inflamed or reddened as their tissues continue to break down.

In a normal healthy circumstance, you should see ammonia levels of no more than 2 parts per million.

Ideally, you should be able to keep that level to zero with weekly regular water changes, along with continued monitoring for poor water quality.


To prevent high nitrate levels, use frequent water changes and monitor your tank when feeding, especially with new foods.

If after 30 minutes the food remains uneaten, remove it before it has the chance to begin releasing ammonia.


Sick Betta Fish
Sick Betta Fish

A newly sick betta will begin displaying signs of illness by appearing lethargic and sitting on the bottom of the tank.

Some fish may simply hang in one place, unable to swim properly as bacteria damage their air bladders.

If you suspect a betta of illness, remove the affected fish to a separate hospital or quarantine tank for treatment in order to prevent spread.


Parasites are most commonly introduced when fish are brought into a tank without proper acclimation time (15 minutes to 1 hour typically).

Fish straight from the pet store can carry all kinds of disease and organisms on-board, which will jump from the new fish to your betta.

Preventing Illnesses

Maintaining a clean, safe environment is the first step to preventing a betta fish’s body from acquiring an infection such as velvet (also known as gold dust disease for the dust-like pattern it leaves.)

Viruses, fungi, and bacteria all thrive in conditions that vary ever so slightly from the ideal, meaning close attention to detail can pay large rewards for the diligent aquarium keepers.

The general term infection can refer to a range of illnesses, fungal infection or a specific disease such as infectious protrusion disease or Ichthyosporidium, but most present in a similar fashion when considering the affected betta.

Signs of Infection

Sick Betta Swimming
Sick Betta Swimming

Redness, swelling, and lines of color radiating around affected scales, bleeding and possible ulcers, scale loss, betta’s fins showing rot, damage, or fraying pelvic fins, a change or darkening in color of regular scale, and behavioral changes such as lethargy, swimming oddly, laying at the bottom, breathing heavily and appetite loss.

Treatment for Fungal or Bacterial Infection

Quarantining the affected fish, cleaning and replacing the water in the tank, providing proper medication and antibiotics as needed, drying out suspected decorations carrying infectious organisms, and monitoring for further health complications.


If your betta has recently eaten something hard to digest, such as bread or fibrous veggies, it’s body will struggle.

The fish will likely sit on the bottom of the tank, unable to pass these foods through their system.

Along with the issues related to constipation, unhealthy foods can mean poor nutrition overall which will lead to a sick, unhealthy fish. To avoid complications, make sure to provide your betta with a proper nutrition and diet.

Swim Bladder Issues

The fish’s swim or air bladder is the air filled organ in a betta that allows for movement throughout the tank.

When your fish gets swim bladder disease, this air becomes either too concentrated or may dissipate, leading it to either sit on the bottom, float awkwardly around, or swim sideways in the tank.

Here’s a video of a fish suffering from swim bladder disease….

Constipation and swim bladder disease in bettas

Swim bladder problems can be incredibly difficult to deal with for the fish itself, as the betta fish will have difficulty eating and reaching their food.

Swim bladder disease can quickly change from simple swim or air bladder issues into malnourishment and further illness if not properly treated.

Resolving Swim Bladder Disease

To resolve swim bladder disease, consult your veterinarian or local pet shop as to which swim bladder disorder medication is right for your fish.

A good first step in controlling swim bladder disorder is to move the sick fish to a quiet, isolated tank so that it is not further stressed and can’t introduce illness to fish in the betta tank.


The term dropsy comes from an old English medical term for swelling in the abdomen caused by gasses or fluids.

The “drop” refers to the way the belly of the fish appears to droop in appearance as it swells. Today it would more likely be referred to as an edema, but either way it can lead to serious health complications in fish.

Signs of a Fish With Dropsy

Swelling around the eyes, bloated stomach, the presence of lesions, scale loss, or abrasions, and becoming lethargic, laying at the bottom, or acting excessively tired and swimming in irregular ways

Cause of Dropsy

Dropsy is caused by a group of several bacteria commonly present in most home freshwater aquariums. An unstressed, healthy fish can handle the presence of these bacteria without much problem.

Unfortunately, by the time the more serious symptoms of dropsy begin to manifest it may be too late.

Treatment for Dropsy

Treatment for dropsy can be difficult and require medications or the use of aquarium salt, but a good place to start is by removing the afflicted fish to a separate tank to prevent dropsy from spreading.

Eggs and Betta Fish

Betta fish keeping can come with the added bonus of additional baby fish if you attempt to breed bettas.

The problem for some female betta fish comes when they become egg bound, which can be an uncomfortable situation where they swim with great difficulty or not at all.

This should pass once the betta is able to properly lay eggs, but if you don’t see them swim normally within a day or two after laying it may be a sign that something else is wrong and that they should be closely monitored for other symptoms of infection or disease.

Do Betta Fish Get Bored?

Blue and Orange Betta Fish
Blue and Orange Betta Fish

Unlike humans, you will never see a bored betta fish.

They are not naturally social animals and do not need companionship or much activity to remain stimulated, although it can be nice to place small toys throughout to make things more interesting for you.

Fish feel hunger, pain, and tiredness, but will likely not be made much more happy by aquarium toys.


If looking for an alternative to lots of little aquarium toys all over the place, consider adding some betta plants and decorations for your curious fish to explore.

Aging Betta Fish

Bettas have a lifespan of 2-5 years, and it’s important that as fish owners we acknowledge that older betta fish will begin to slow down.

Unlike a healthy younger fish, an older fish is more likely to get sick as its immune system starts to wear, meaning the betta fish lays on the bottom more than usual.

Dead Betta Fish

Dead Betta
Dead Betta

The unfortunate fact is that some betta fish laying on bottom of the tank may in fact be a dead or dying betta fish. Look for typical signs of life such as gill and fin movement, heartbeat, and eye movement, and try to notice any foul smells in the tank.

Most dead fish will float to the surface if slightly jostled, as the gas expanding inside is more buoyant.

While a sad moment in any aquarist’s life, the dead fish should be removed as soon as possible to prevent ammonia releasing as it decays and potential spread of disease if that’s what caused it to die.

What To Do If Your Betta Fish Is Laying On The Bottom Of The Tank

  1. Check to see if the fish is simply sleeping!
  2. Monitor for additional symptoms, and make note of specifics
  3. Take this information to a qualified source such as the original breeder, a veterinarian, or the pet store
  4. Follow directions with any medication to the letter, all of the way to the end


Throughout today’s article we’ve looked at what betta fish owners should do if they see their betta fish laying on bottom of tank.

While it may simply be that the fish is asleep, it may in fact be something more serious such as swim bladder disease or another illness.

If this is the case, knowing what other symptoms are present on your fish is important in ultimately assessing and curing whatever is wrong.

Feel Free To Share!

As always we hope that you’ve enjoyed this piece and that it has answered all of the questions needed to keep your betta alive.

Feel free to share this article about betta fish laying on bottom of tank with any fellow fish fanatics you may know, and we wish you the best of luck on your aquarium adventures.

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