Why Is My Betta at The Bottom of The Tank? [11 Reasons]

green betta fish

It must be exciting to welcome the colorful and vibrant Betta into your aquarium. But I am sure tension takes over the excitement when you find your Betta at the bottom of the tank and wonder why.

Betta can stay at the bottom of the tank because of natural causes, uninhabitable ambiance, or poisoning and disease. Your betta may be just resting underneath. But ammonia or nitrate poisoning, faulty filtration system, and many more can be the reason your betta is at the bottom of the tank.

If you are worried about your batta being on the bottom layer of your tank, this article will show you the possible causes behind such behavior. Let’s investigate the underlying reasons together. Shall we?

11 Reasons For Your Betta Fish To Be At The Bottom Of The Tank. 

Your mind should not travel to the worst-case scenario when you see the unusual pattern of your betta fish. Sometimes the issue might be very normal, and it might not be about your betta fish. On gist, there are three broad reasons why your betta fish is at the bottom.

  • Natural causes
  • Inhospitable environment

Let’s dive into the possible causes and diagnose the terminal reason for your betta fish laying at the bottom of your aquarium.

Natural Causes

Natural causes mean those harmless reasons for which your betta can be on the bottom layer. Not always being on the bottom of the tank means something inauspicious. So, instead of turning on the panic button in your brain, diagnose the underlying cause.

1. Enjoying a Nap

Betta fish enjoys a good napping time or resting period. And their favorite position is laying on the side at the bottom of the tank. Usually, a betta enjoys resting their body on some surface, like leaves. But it is not unusual to float on the bottom, especially in absence of a surface. You can tell whether your better is just sleeping by monitoring its movement.

Even though their whole body lays in a resting position, their gills, and mouths move in a rhythm. Sleeping time can be another way of telling the fish is resting. If you want to be absolutely sure, turn the light on and see if betta wakes up or not.

2. Older Bettas

Betta’s lifespan limits to 4-5 years. After they mark their 5th birthday, their energy level drops down. As the bettas get older, they prefer to swim around on the bottom of the tank. This is completely normal and harmless.

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Bettas are peaceful in nature, and it is truer for the older ones. Since the water flow is gentler and calmer underneath, the bettas enjoy their stay there. Actually, the bottom layer is perfect for their inhabitation for their depleted energy.

3. Pregnant Bettas

If you are an owner of a female betta, chances are the reason it is laying at the bottom is because of its pregnancy. The duration of pregnancy lasts for 1-2 weeks. The babies will hatch within 3 days. 

You can be sure about it by checking the swollen belly. This also may indicate egg-bound or constipation. But to dissect the pregnancy from other reasonings, check for white dots on their belly and white line on their sides.

Inhospitable Environment.

Dumping the fish into a pile of water and giving them food doesn’t define good parenting. Even before bringing the fish home, you have to build a cozy and amiable ambiance for your little fish. Hostile and uninhabitable environments can play a role for your betta floating on the bottom.

1. Not Adequate Water:

Betta fish requires three to five gallons of water for each fish. The water quantity should depend on the number of fish you have. Also, as the betta gets bigger, the water level should increase as well. Betta prefers calm, motionless water with a Ph level between 6.8 to 7.5. Make sure to change 20-30% of the water every two weeks.

2. Not Adequate Space:

Bettas are quite independent and prefer to swim around the tank. If you put them in a smaller aquarium, chances are they will roam around on the bottom for their restricted movements. Bettas’ favorable place includes a bigger aquarium with caves built-in to rest and hide. 

In a smaller tank, waste produces spread quickly which may be poisonous for the bettas. Also, the other occupants of the tank and bettas tend to get into fights over the territories in a smaller aquarium.

3. No System for Filtration:

Decomposition, leftover foods, waste, and leaves produce nitrogen as a by-product, and the bio-load mixes with the water creating a poisonous concoction. That is why a good filtration system must be installed for clear water and less poisoning.

Filtration helps to increase the oxygen level. So, your betta can inhale and exhale in peace and without the risk of infiltration of poison. But you must be careful about the pressure level, size, noise, and the strong quality of the filters. If the setting is not compatible with your bettas, it may fail to serve its purpose.

4. Temperature Fluctuation:

Bettas originate from tropical land with an average temperature of 80 degrees F. So, the ideal and cozy temperature for them is 75 to 82 degrees F. Especially if the tank location is in winter-based areas, the bettas are at dire risk. Because they can’t survive under 65 degrees F.

In order to keep them warm, they tend to float on the bottom, farther from the winter chill. So, keep the water warmer for them and check whether they float on the upper layers or not.

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5. Direct Sunlight: 

Keeping the temperature warm but halting the sun exposure may sound contradictory. Hear me out. When you keep the water temperature on check, you have full control of the temperature settings, and you can alternate depending on the preference of the bettas.

But, when you place the tank underneath direct sun exposure, you almost cook the bettas by exposing them to overheated water. Since you can’t control the sun’s temperature level, excess exposure hinders them to swim on top. Also, it helps the algae to grow quicker, which isn’t good news for your bettas.

Infected with a Disease

Well, if the diagnosis doesn’t indicate any cause from the upper sections, chances are your bettas have been exposed to contamination or developed a disease. But instead of panicking, think the laying on the bottom as a symptom of probable serious disease. Let’s see what possible disease it may have been attacked with.

1. Nitrate Poisoning:

An aquarium plays a life cycle on its own and nitrate is produced by the waste and compost of the fish. An overfed fish produces more waste, which produces more nitrate inside the tank. Also, if you don’t change the water often, the nitrates produced keep amassing.

This creates a very unhealthy environment for the bettas and if they are exposed to poisoning, they tend to lethargically lay at the bottom. Even though the safety level for the nitrate is 20-40 PPM, long exposure to even 20 PPM might prove fatal for the bettas.

If your betta is looking pale, lethargic, and discolored, it might have nitrate poisoning. Also, monitor their appetite level and movement of their gills, they also indicate poisoning. To be absolutely sure, check the water in the tank with a test kit for the exact nitrate level.

2. Ammonia Poisoning:

Ammonia is another deadly poison that roams around freely around the tank and might be fatal for the bettas. Why the ammonia level spikes up inside the tank is a complex question. But if the number of inhabitants has grown exponentially, and the overfeeding continues for a while, the ammonia level will rise.

Also, if the tank is too immature to produce favorable bacteria which reduces the ammonia level and you import your bettas at that stage, it might be exposed to ammonia poisoning. While they are infected with poisoning, they tend to lay on the bottom, gulping for breath, almost like an asthma attack.

3. Swim Bladder Disorder:

Bettas’ bladder control distorts when they are overfed, constipated, or eggbound. This hinders them to swim around freely, and they tend to lay lazily on the bottom layer of the tank. Sometimes, their movement seems odd and unsynchronized because the overfilled bladder defies following their command.

If you notice a swollen belly but no white dots or strips, this checks out the pregnancy and narrows it down to swim bladder disorder. For a healthy bladder and bowel, lower their feeding ratio, and keep them on a diet to be precise.

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Betta Discoloring and Laying on the Bottom

Betta losing color is one of their ways to indicate that something is not right. Discoloring happens mostly due to stress, old age, and disease. Stress is the most common cause of discoloration.

As mentioned earlier, bettas are sensitive to temperature upheaval. Sudden temperature swings can affect their mood and stress levels. Also, unhealthy bowel movements, overeating, and congested environments can increase their stress level and make them lose color, feel lethargic, and push them to lie on the bottom.

Also, discoloration and staying at the bottom can be a sign of aging, which can initiate after 4-5 years. Ammonia or nitrate levels in the water can play a role in the discoloring of the bettas. But once the water change is managed and the toxins deplete, their coloring will come back again.

Betta Not Eating and Laying on the Bottom

Depending on age, size, and appetite, a betta requires 2-4 pellets per day. A healthy and active betta should be happy with such portion and swim around freely. But when the bettas deny their usual meal, it must be due to overeating and constipation. A constipated betta will lay lazily on the bottom.

Constipation is a challenging condition for the bettas which can lead to premature death. But the easy solution is to provide them with fibrous food like­­ peas. Also, for 2-3 days, lower the amount of food. The bettas can happily live on the algae. In that way, their unprocessed food will be digested, and their appetite will return.

Betta Gasping at the Bottom of the Tank

Betta’s gasping is not a good sign, and it indicates that it has poisoning, either Ammonia or nitrate. Due to an excess amount of nitrate or ammonia in the water, the bettas’ normal breathing pattern is hindered.

If the bettas are gasping, change the water at the earliest moment and add nitrate neutralizer to mitigate the effect. Also, make sure the temperature is suitable for the bettas. Because hot water can be the reason for gasping and staying at the bottom for bettas.

Betta Staying at the Bottom After the Water Change

When the water is changed, the temperature alteration startles your bettas. That causes panic and places them at the bottom of the secure place. That is why it is not wise to take the bettas out while changing the water. Make sure to change the 20-30% of water in a cycle, instead of 100% water changes.

Final Words:

Laying on the bottom of the tank for your bettas doesn’t always indicate something ominous and sinister. But that doesn’t relieve you to ignore this act. Instead of jumping to your own conclusion, diagnose the underlying reason by troubleshooting the possible causes.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of AcuarioPets.com. 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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