Why is my betta fish laying at the bottom of the tank?

In this blog we will discuss the possible reasons why bettas might be at the bottom of the tank and will also discuss how to diagnose this issue.


In this blog

  • Why is my betta fish laying at the bottom of the tank?
  • What are the possible reasons for betta fish to lay at the bottom of the tank?
  • Summary 
  • Frequently asked questions
  • Reference

Why is my betta fish laying at the bottom of the tank?

Betta fish is one of the most beautiful and popular aquarium fish. With their long fins and bright colors, they swim around your aquarium at their best and show off their beauty.

If your betta fish is laying at the bottom of the tank and breathing heavily, it is necessary to take action as soon as possible to cope with it.

Possible reasons for such behavior in betta fish are ammonia poisoning, nitrate poisoning, and the hot temperature in their tanks. These three are major reasons for such behavior. There are several other reasons too.

What are the possible reasons for betta fish to lay at the bottom of the tank?

Understanding your betta fish behavior could help you determine when you must take action. Here are some of the most common causes why betta fish lie at the bottom of an aquarium.

Ammonia pollution in bettas tank

Bettas are greedy eaters and are famous for producing lots of waste, which in turn increases the levels of ammonia in their tank. It is a well-known fact that ammonia is a very toxic and detrimental organic pollutant, which can seriously damage bettas gills.

The main issue with ammonia is that you can’t see it. One should practice good tank maintenance and monitoring to prevent these levels from rising sharply.  This means regular water changes and an efficient filtration system are essential to bettas.

If your tank doesn’t have an efficient filter in place, ammonia levels will continue to rise and weaken your betta fish immune system.

Compact tanks or overcrowded environments tend to suffer more from ammonia issues. Use a suitable testing kit to inspect ammonia levels. The only safe level is 0 PPM. 

Anything beyond this level could be detrimental to your betta fish. Make sure you are housing your bettas in a spacious tank, where they can swim and breathe effortlessly.

Nitrate pollution in bettas tank

Nitrate is another organic compound produced by fish waste like leftovers, feces, and debris. However, it’s a byproduct of bacterial breakdown. Bacteria in a well-cycled and circulated tank will convert ammonia to nitrites and then nitrates.

In comparison to ammonia and nitrites, nitrates are less harmful than ammonia. However, they still do a lot of damage to bettas, as it works as a slow poison. Nitrate spikes also make betta fish lazy and weak and might cause them to lay at the bottom of the tank.

It is vital to keep an ammonia testing kit and monitor the water to know the levels of organic pollutants in bettas tanks.

Hot temperature in bettas tank

Temperature plays a vital role in betta’s good health and longevity.  Bettas are hardy species and can tolerate some temperature fluctuations but temperature shock is something different and is a real threat to betta fish. 

Bettas are tropical freshwater fish and do enjoy warmer temperatures. However, the excessive temperature during the summer season will lead to multiple health issues.

It is a well-known fact that warm waters release oxygen much more rapidly than cold waters. 

It is not exactly the temperature that is creating a problem rather it’s the oxygen-deficient environment that’s affecting bettas.

In an oxygen-deficient environment, your betta fish will be gasping for air at the bottom of the tank.Even with their ability to breathe atmospheric air, water without oxygen is a serious problem.

Betta fish is sleeping

Betta fish sleep just like humans and follow the same general sleep cycle as humans. They like to rest at night and stay active during the day, so that they can function properly.If they don’t get proper sleep at night, you might find them napping at the bottom of the tank.

Older bettas usually spend most of their time lying in plants or at the bottom of the tank. There is nothing to worry about if old bettas sleep more.

Some bettas are just lazy. If all is well with your betta or tank, it may just be lazy. While you should let him sleep in longer, make sure he still gets enough exercise.

Bettas are very particular about their space in tanks and choose unique spots to sleep or rest. They can sleep in nooks, rest on the substrate, or even sleep on top of their favorite plant leaves. 

It is better to leave them in a dark quiet spot during the night to make sure that they’re getting proper sleep.

Excessive water currents in bettas tank

Betta fish do not perform well in strong water currents, because their huge fins are purely ornamental and don’t do much to help this fish swim. If you have significant flow coming from the filter, your fish might be probably tired due to the weight of their long-flowing fins.

It takes more energy with those huge fins to continuously fight a strong current of water. Perhaps your betta fish has given up and decided to rest on the bottom of the tank.

A good quality filter for bettas is those that don’t make too much noise, have low currents, take up very little space and have good strength.

Betta fish might be aging

Betta fish have a very short lifespan. In good aquarium conditions, they will live between three and five years. If you have them for a while, they can suffer the effects of aging.

Like human beings, old betta fish tend to slow down as they age. They simply don’t have the energy to swim around their habitat or aquarium as they did when they were very active at a young age. Their bodies begin to slow down and they have a harder time keeping up with other younger fish.

Therefore older betta fish prefer to rest more. Your fish could start laying down on leaves, and betta logs or spending more time resting on the substrate at the bottom of the tank.

It is tough to determine the age of your betta unless you haven’t raised one for the very beginning, i.e fry stage. To be honest, even if you bought your fish a few months or days ago, they could have spent some time already at the store or with betta breeders.

Swim bladder disorder in betta fish

The swim bladder is an important organ for your fish, as it is needed to maintain balance during swimming. 

When betta fish suffer from swim bladder disorder which is very common in them due to constipation or overfeeding, they start swimming in strange patterns, have difficulty moving, or lay at the bottom of the tank.

Sickness in betta fish

If bettas are looking lazy and spending most of their time laying at the bottom of the tank, they could be severely ill. Several diseases affect bettas like ich, bloat, dropsy, and many more to list down due to weaker immune systems.

Bettas might be simply spending time at the bottom

There is nothing to worry about if your betta fish is spending time at the bottom of the tank because it might be simply resting at the bottom and chilling on its own. Being a betta owner you should understand your fish’s behavior.

If they are laying at the bottom with their fins still in motion, it might just be relaxing. Bettas are known for their massive fins which makes it difficult for them to swim as it takes a lot of their energy to drag those fins.


Bettas fish are very sensitive to poor water conditions and especially ammonia spikes and nitrite levels in their tanks. It is important to keep their levels in check, if this level increases beyond a certain value then they will lay at the bottom of the tank due to underlying injuries or diseases.

Various diseases in betta fish are caused by a stressful environment and poor tank maintenance practice. It is important to maintain pristine water conditions in bettas tanks. Check for stressors and remove them for the betterment of your betta fish.

If you fail to remove stressors from the betta’s tank, your betta will spend most of its time at the bottom of the tank only.

It is not necessarily bad if you see the betta fish laying at the bottom of the tank. Sometimes they just need rest or want to spend time alone. But as a responsible betta keeper you still need to be prepared if the cause happens to be serious.

Caring for bettas is not a tedious task if you are following proper tank maintenance practice. You should spend some time daily with your fish to understand their behavior.

Frequently asked questions

Do bettas always spend time at the bottom of the tank?

No, bettas occupy the middle and top regions of the tank and rarely spend time at the bottom of the tank.