Why is My Fish Lying on the Bottom of a Tank? A Complete Guide

Why is My Fish Lying on the Bottom of a Tank? A Complete Guide

A fish lying on the bottom of a tank could be doing so for a variety of reasons like water quality imbalances, illness or intoxication. It’s necessary to note that some fish use the floor surface to relax, so recognising the symptoms of an unhealthy fish is important.

Why is My Fish Lying on the Bottom of a Tank?

In most cases, a fish will lie close to the floor of the tank when ill or injured, and there may be various signs that can help you perceive this and/or find the cause.

Such signs can include weakness, loss of appetite, heavy breathing, slow movements and loss of buoyancy. We elaborate on this below.

Why is My Fish Lying on the Bottom of a Tank

Appetite Loss 

If your fish isn’t eating and remains mostly at the bottom of the tank, there’s a high chance it may be unwell. Illnesses such as dropsy, swimming bladder diseases and common constipation can cause appetite loss.

You may have to try different foods to encourage your fish to eat. Live, fresh and frozen foods are good choices for sick or recovering fish, and you can also add blanched vegetables or change fish flakes.

Breathing Heavily

If your fish seem to be laying on the floor of the aquarium and gasping for air, it’s most likely linked to water parameters. Your tank water could have ammonia poisoning, nitrate poisoning or temperatures that are too hot. In this case, you’re best to fix water conditions as quickly as possible. If the problem is heating, cool the tank slowly as sudden changes can cause extra stress on your fish.

Laying Upside Down 

Being upside-down is an indication that the fish may have swim bladder disease. This is where there has been a malfunction in the shaping of your fish’s bladder, and it can’t balance properly. Make sure to check and maintain healthy water parameters in the tank and work at treating some of the core causes of the disease, such as constipation.

In extreme circumstances, don’t hesitate to take your fish to the vet.

Laying on Side 

Your fish may not always be injured or sick when it’s lying on the bottom of the tank. If it’s laying upright or on its side with no other worrying symptoms showing, it may just be relaxing or asleep.

You can give your fish more décor, plants and hiding options if you want them away from the substrate. There’s plenty of sleeping platforms and artificial caves you can buy specifically for this purpose.

Is it Normal for Betta Fish fish to be lying on the bottom of a tank?

Why is my Betta laying on the bottom of the tank

Like many other fish, bettas may be lying on the bottom of the tank for a variety of reasons, some harmless. Understanding healthy and unhealthy symptoms of your betta can help you determine the best ways to help them.

Sleeping Betta Fish

A healthy betta naps often. Providing a resting place for your fish to sleep on or in can help ease the stress of

wondering if it is just sleeping or not.

However, if you aren’t sure if your betta is simply tired, watch for unusual symptoms that might indicate illness. For example, feebly swimming, drooping fins or having no appetite.

Older Bettas 

Some older betta fish don’t have the stamina to swim strongly, so it may be more common to see it resting near the bottom of the tank. The average lifespan of a betta is between 3 and 5 years, and slow, gentle water flow is essential for them in their later years.

Betta isn’t Resting

If your betta is showing symptoms of having an illness or injury, it’s important to check and maintain healthy water parameters straight away. Reduce water flow in the tank and do your best to correctly diagnose the problem. If symptoms continue, you can take your betta to the vet.


Diseases That Can Cause Fish Lying On the Bottom of a Tank

There are a range of diseases that may cause your fish to lay on the bottom of the tank. Noticing a disease’s first sign can help you deal with the illness at its earliest stage.

If you’re noticing symptoms that indicate one of these diseases, always quarantine your fish in a hospital of quarantine tank as a precaution. Such tanks are a stable and confined environment of healthy water patterns and temperatures, to assist in nursing your fish back to health.

Sickness & Disease

In most cases, fish are more likely to get an infection or disease because of a weaker immune system, often caused by stress or bad environmental conditions.

Diseases like ich, bloat, dropsy, and others can affect more vulnerable fish. Staying ahead of water conditions and ensuring parameters are within the acceptable range can help prevent many of these.

Ammonia Poisoning

It’s pretty simple to monitor for ammonia poisoning. You can use an ammonia test kit to find the concentration in your aquarium.

To prevent high ammonia levels, ensure that your tank is kept clean, with regular maintenance on water changes, cleaning the substrate, avoiding overfeeding and having an effective filter.

Nitrate Poisoning

Similarly to ammonia poisoning, you can test the tank water for nitrate concentrations. If there’s evidence of nitrate poisoning, it’s important to perform significant water changes.

Fish with toxic nitrate poisoning might be breathing heavily and show pale discoloration, usually laying at the bottom of the tank.

Aggressive Fish

Aggressive fish can sometimes be the cause of fish laying on the bottom of the tank, by attacking and injuring them. It may be necessary to remove the aggressive fish, or place the timid fish in a floating basket to avoid confrontation.

Swim Bladder Disease

Swim bladder disease, as we mentioned before, is the temporary or permanent deformity of a fish’s bladder that causes them to swim unbalanced and fall upside-down.

This disease is frequently caused by overfeeding or the inability of an animal’s body to digest some food. Thawed green peas or daphnia can help combat it.

Once your fish feels better, it should start swimming as usual. If there’s no change however, see a vet for suitable medication.

Other Stress-Related Issues

Sometimes a fish that’s been harassed, or is under stress, may sit at the bottom of the tank. You can try offering it more hiding spots with plants and rocks, or move it to a private tank to avoid these problems.

Other Possible Causes of Fish Lying On the Bottom of a Tank

Fish Fungal Disease

There are other causes not related to disease that could cause your fish to lie on the bottom of the tank.

Displaying Territorial Behavior 

Some territorial fish may stay on the bottom level of the tank and claim a portion of its land. If it’s posing a danger to other fish in the aquarium, it may be necessary to move the aggressive fish into a new tank.

Water Temperature is Too Cold

A sustainable temperature for your aquarium is about 77 degrees Fahrenheit. If the temperature gets below these levels, the metabolism of most tropical fish starts to slow down, causing them to feel lethargic and weak, lying at the bottom of the tank.

In this case, use an in-tank heater to gradually increase temperatures. Make sure there is no sudden temperature change however, as it could put unnecessary stress on your fish.

Water Temperature is Too Hot

Higher temperatures make it more difficult for oxygen to be absorbed in the water during gas exchange. This can lead to your fish breathing heavily and sitting stagnant at the bottom of the aquarium. Warm water may also increase the metabolic rates of fish, making them eat more and produce more waste.

Again, it’s important to gradually shift temperatures back to normal, avoid extreme changes. You can use a fan to cool off the tank slowly, and an air pump to restore oxygen levels.

Water Quality and Unstable Parameters

Significant changes in water quality can lead to having unstable water parameters. This means your fish may be more likely to be affected by toxic wastes and stress that can impact its health. If your fish is lying on the bottom of the tank, make sure to check the aquarium water and parameter levels first.

The Aquarium is Too Small

It’s a common misconception that fish can thrive in small, empty tanks. In reality, this can create some unnecessary stress on your fish. Along with that, empty tanks give fish few options to lie on and they may choose to sit on the bottom of the tank instead.

Creating a vibrant and interactive tank can keep your fish healthy and thriving. Adding plants, decor, caves and most importantly, space, all work to make a strong environment.


Some fish follow the same overall sleep pattern as humans and a lot of the time, they use the bottom of the tank to rest. Bettas are known for finding interesting places to sleep, like tucked in corners or in the foliage.

If you notice your fish sleeping in the morning, consider changing you light’s night settings and leaving your fish in a dark, quiet environment at night to ensure they get the necessary rest.

Extreme Current

Some fish don’t cope well in powerful water flow and can result in a lot of stress if there’s a strong current coming from filters or pumps. To decrease water flow from your pump, you can attach a sponge filter, or redirect the flow towards plants and decorations.

It’s common for fish to rest low in the water after being removed from a fast-flowing tank.

Bottom Dwellers and Feeders

Many fish and aquatic animals are bottom dwellers and naturally stick to the floor of the tank. For example, loaches, corys, catfishes and plecos. Other fish are bottom feeders, meaning that they prefer the floor of the aquarium because that’s where they can find food easily. These fish are usually feeding all of the time and work to keep your tank fairly clean.

Older Fish

Aquarium fish generally have a lifespan between 3 to 8 years. As they age, they have a higher chance of resting near the bottom of the tank as they naturally become more lethargic. If your older fish tends to have short breaks to rest between periods of activity, there’s not much need to worry.


Newcomer fish in unfamiliar areas may choose to lay at the bottom if your tank lacks other refuge areas. However, healthy fish should recover quickly and leave the substrate to explore their new home.


Tips for Beginner Fish Keepers

Some fish, like bettas, spend a bit of time lying at the aquarium floor. It’s recommended to do some research as to what activity levels you should expect with your species of fish. Other tips include:

  • Regularly check your equipment is on and working properly
  • Regularly check that you fish are eating and behaving in their usual fashion
  • Set up a periodic cleaning routine for the tank, for changing the water and vacuuming the substrate
  • Don’t overfeed your fish

Final Thoughts – fish lying on the bottom of a tank

If your fish is laying at the bottom of the tank, make sure to double check water quality and tank settings before trying to diagnose the problem.

Ultimately, getting familiar with your fish’s behaviour and habits can help you notice when something doesn’t seem quite right. This way, you can look after your fish in the most effective way possible.


Why is My Fish Laying On the Side?

Why is My Fish Laying On the Side?

In this article we address the question: Why is my fish laying on the side?

Does this mean your fish is diseased? The short answer is – possibly, however, there are many factors that may result in a fish laying on its side. Gene traits, diet, habitat conditions, opportunistic pathogens, fish syndromes and water quality all may play a role.

Why is your fish lying at his side?

There are many possible causes for the fish to lay flat on the bottom of the tank. Not every reason is terrible, but it’s a signal for you to watch for future changes in your fish behavior.

Use position and behavior to diagnose and treat common problems. This article will help you learn how to solve and analyze each difficulty you face.


Cause for a fish that’s laying on the side

The fact that the fish is acting strange and has sunk, laying on his side at the bottom, is frustrating to any fish keeper. It can happen with all species of fish.

The early stage of any problem or disease can be detected right away when you notice any strange swimming or behavior.

If your fish is swimming and lying at the bottom, that should signify that something is incorrect.

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What if they’re at the bottom of the tank breathing heavy?

Fish laying on the bottom of the tank and breathing deeply require action as soon as possible. Usually, rapid breathing is caused by some pollutant or toxic in the water.

In most cases, it is poisoning by ammonia, nitrite, or other nitrogen. This behavior can also occur when fish are exposed to high temperatures.

Perform tank tests to gauge temperature and nitrogen levels. Next, adjust your parameters and maintenance schedule to keep them from spiking.

What if your fish is at the bottom of the tank not moving?

If your fish is laying and not moving, calmly observe if the fish is making any movement, has some strange stain on the body, as are their fins and their breathing.

Once you have enough information, take some action indicated in this guide that makes the most sense. Asking for help from experienced aquarists and a veterinarian is a great way to go.

Treating a sick Fish

Don’t be intimidated by the different medications available for your fish. First, you’ll need to diagnose which disease your fish has and choose the best treatment to treat it.

If the tank has plants or snails, it must be taken out in another tank; some medicine can be poison for this type of life.

Remove is the best way to prevent your favorite plant from dying from drugs. Let’s examine some diseases that might explain your fish lying on its side.

Depending on where your fish has been kept, there could be a water quality symptom.

Is it normal for my fish to lay on the bottom of the tank?

There are several reasons for fish would lie on the bottom of a tank, some of which are common and harmless.

Learning to recognize some behaviors can help you to solve a lot of issues. Know when your fish are stressed helps prevent your animal from getting sick.

Sickness & Disease

Several diseases can plague fish health. Typically they experience more illnesses when they are with weaker immune systems.

Diseases like Ich, Bloat, Dropsy, and more are usually caused due to stress or lack of proper care. Keep your head on the water conditions and make sure all the water parameters remain within the recommended range.

When your fish is stressed, they got more susceptible to disease. It is essential to maintain adequate and stable water conditions.

Tailor Fin Rot

Fish Fungal DiseaseFin rot can usually be fixed when treated with Ampicillin or Tetracycline. Clean water will reduce the chances of further fin rot.

You can also use a natural antifungal for two days. Make sure to keep regular water changes and to vacuum on a scheduled basis. Fin rot is probably not the most critical reason your fish lies in the tank, but it is a severe disease.

Fungal Infection

Fungal infections are highly contagious and are easily spread through other tanks’ occupants. Adding salt to the tank can cause serious problems; overdosing salt can damage fish, invertebrates, and plants.

Add salt to the proper concentration to treat a fungal infection may help; water changes must be carried out before each application to keep saline levels under control.

Ammonia poisoning

The changing conditions of water’s chemistry can cause many of these issues. If the ammonia level in the tanks is too high, you can perform a partial water change.

Remember to cycle your aquarium before adding fish continuously. Keep the tank clean, avoid overfeeding, and correctly size your filtering capacity.

It’s best to remove a large quantity of the water every week; the more frequently and the greater the amount, the better; remember to stabilize incoming water parameters with aquarium standards.

Nitrate poisoning

Fish with nitrate poisoning can have a high breath rate and look pale or discolored. They may seem lazy, moving strangely. Proceed with the water test and also a partial or total change.

Swim Bladder Disorder

It affects the swim bladder of the fish, an organ that helps the fish fluctuability. In medical terms, the fish suffer either positive buoyancy or negative buoyance.

Symptoms include sinking to the bottom or floating at the top of the tanks, floating upside down or on their side, or having trouble maintaining a normal position.

Affected fish can eat every day or have little appetite. When serious buoyancy problems exist, it is possible that the fish will not feed usual or perhaps even reach the surface.

Symptoms such as a dislocated belly and curved back can be present on affected fish. A swim bladder defect is the consequence of temporary or permanent impairment of the swim bladder.

There may be the pressure of a swollen stomach, an accident, or a bacterial infection. Sometimes after overeating, fish might swallow air on purpose. To cure your fish, you need to know the origins of its bizarre behavior.


Dropsy Disease in Betta FishDropsy is not disease-specific; it occurs when his belly swells and causes scales to protrude sideways.

The dropsy syndrome is fatal if not quickly treated. Early signs of dropsy are challenging to diagnose.

Dropsy is a direct consequence of an infection indirectly caused by poor water quality. Proceed immediately with the total water change, aquarium cleaning, an antibiotic medication.


Velvet usually appears after a tank is not adequately treated using a water conditioner. If your fish is scratching its skin on aquarium décor or rocks, he likely suffers from velvet.

Clean the tank and add water changes will help remove the velvet. Keep water parameters stable and perfect. You should use medication for Velvet disease in case of infection.

Ich (white spot disease)

Ich (Ichthyophthirius multifiliis) is a protozoan and is found in many aquariums and reservoirs. A healthy fish’s immune system shields it from ich itself, but it can be vulnerable to stressed or injured fish.

Infrequent water changes, improper water temperatures, and poor food choices can significantly weaken a fish’s immunity system.

To treat ich, raise the temperature to the equivalent of 80 degrees Fahrenheit. Maintain water temperature at 82 F for 14 days; this should break the reproduction cycle of the parasite.


Betta Fish PopeyeMore than one culprit may be identified for pop-eye, but regular tests and water changes will be the first thing you need when seeing eye bulging in your fish.

If the water conditions are in a good state, treat your fish with a medication to kill Positive gram bacteria or use a drug for cloudy eyes or pop-eye in the bottle.

The water is too hot or too cold, and O² levels.

Cool water delivers oxygen much faster than warm water does. If your aquarium is filled with no oxygen, then your fish is choking for air.

Cool the temperature in your tank slowly if you have a fan or room air conditioner. To inject oxygen quickly into the water, use an extra pump or air compressor to help in gas change.

Ideally, the water temperature in your tanks should be the most suitable for the species you keep. If the temperature falls below the animal’s tolerance, your fish starts to stifle its metabolism.

Oxygen gets absorbed slower. These combinations of events can cause your fish to become lethargic. Use an in-tank heater to raise the temperature in the aquarium steadily.

Low oxygen levels make the fish passive and quiet, as well as low temperature. Keep the aquarium well-aerated about its temperature.

Extreme current

Some fish don’t cope well with strong tides. If you see considerable flow coming from a filter or an air pump, your fish can be exhausted.

Add a sponge filter to restrict the water flow to your filter. Alternatively, it’s possible to direct the current towards the décors. Your fish might have given up fighting against water flow and settled to rest on the tank bottom.


Some species of fish do have excess weight; check the body of the fish to avoid overfeeding. A lazy fish should also have a good appetite and can continue swimming when it wants.

If the behavior of your fish starts suddenly to change, watch out for additional signs of trouble and be proactive and make a water change to be safe, constantly checking the parameters with good quality tests.

If you see a fish in your tank laying on his sides, think that doesn’t always have to be a problem. Sometimes fish sleeps and relax on his sides. Specially bettas.

Old age

Old-age fish no longer have the same vigor as their younger companions and enjoy their quiet time in the aquarium corner.

Your fish has lived a long and happy life and loves to lie down when they want. They can usually quickly wake up to feed or go to another spot. It’s not a problem to be concerned if an old fish may lay over plants or at the substrate.

Physical damage or injury

A fall, encountering other aggressive fish species, or other mechanical damage can cause your fish to stay laying.

If it was injured during transportation or has a swim bladder disorder, it could die without medical intervention.

If your fish is struggling with some trouble and does not improve from treatments, then it’s probably too late. I suggest considering a humane way of euthanizing it.

External or internal parasites

Parasites BettaSymptoms usually involve reddening blood vessels, white feces, and swollen belly.

It is a disease gateway for bacterial infections, which cause bloating, skin infections, fin rotting, and many more.

Always inspect your fish and look for all potential signs when there are. The use of anti-parasite medications is necessary.

Just take it easy

It sometimes doesn’t feel worth worrying if a fish lies on his side. If pelvic fins keep coming in motion, then your fish may relax.

They may undergo movements to be able to rest under surfaces. Laying rest is normal, and no need for any fear! Check their habits. If your fish species like to sleep in this way, you’re OK to relax. Please take a peek at the fish behavior inside their tank.

Bloating from swallowing too much air

When a fish uses swim bladders, they contain two bags. This more powerful one connects directly to the stomach. This can result in a disfigured swimming bladder and associated disorientations of buoyancy. In this case, offer food with high fiber content.

Bored Or Depressed

Fish are curious animals by nature and constantly contact the environment and the tank mater. In the wild their exhibit exploratory behaviors, like find food.

Fish can get bored in places without plants, decor, being inside tiny spaces. A bored fish can even scratch its fins on decoration surfaces as well as rub against the substrate.

Developing health problems

It is not uncommon for healthy fish to lay around the tanks because they’re sleeping, acting lazy, or bored.

Sometimes you’ll realize your fish is stressed or tense for 1-3 days before clearer symptoms appear. Be worried if they show signs of begin developing another disease. Test the water and, if needed, proceed with maintenance.

The aquarium is not large enough.

Many new fishkeepers mistakenly believe fish can live anywhere. If your fish has been trapped in confined conditions, they will not thrive for long.

Try increasing the tank size; you can also provide an array of enrichments for your fish, like caves, plants, and natural decorations. All this will make your fish happy and healthy. Give the fish a little extra room for exploring.

Do your research

This article was meant to cover just some basic details about this symptom to raise awareness among fish keepers.

This article is not intended to substitute for diagnosis prognosis, treatment prescriptions, and individualized veterinary medical counseling.

When animals develop distress, you should first take them to a veterinary center. If you think an infestation is on your fish, you will need to do additional research about ways to prevent this issue. The articles are accurate to the best of the author’s knowledge.

Offer a fresh diet

Bloodworms, brine shrimp, and fresh vegetables are offered as snacks, and the high-quality commercial meal makes fish more healthy.

It’s in the water

Cold, poor, and neglectful water quality can cause diseases. Get to know about your fish personality to see how he usually acts.

Polluted water will allow you to know when he changes his routine and maybe starts to develop some disease.

You should do the following if you want to ensure optimum water condition. Perform weekly water changes and tank and substrate cleaning to ensure proper health.

Also, offer a varied diet and taking care of your fish. Your fish should be in a tank with the perfect setting for him to thrive through posteriority. Hot water can speed up your pet’s metabolism and shorten your fish lifespan.

Similarly, cold water can cause your animal to be lazy and sit on your side. You should change their water often; the more, the better.

During the water change, use a siphon and vacuum the substrate, removing all the dirt stuck or on it, lift and clean the decorations, rocks, and trunks.

If done correctly, this will ensure that your water will be kept clean and free from pollutants. Make sure always to test your tank water to set standards and test your tap water to see what to fix.

Always condition your water with specific products for aquariums; this will ensure the removal of toxic substances such as chlorine and heavy metals. Have an accurate test; low-quality tests cause confusion and errors for the hobbyist.

Is your fish lying on its side but not dead?

Why is My Fish Lying on the Bottom of a Tank

Overfeeding can cause stagnation and swim bladder disorder. The swim bladder is an organ that helps bony fish to remain at a certain depth by controlling their density relative to that of water.

Fish use such a system for buoyant to move on the water. The gas expands with lighter pressures helping the fish to rise while being compressed as the fish dives.

Several signs of overfeeding may cause swim bladder disorder, and many people don’t know precisely how easy it is for fish to get overfeed.

Is your fish lying on the bottom of the tank?

Not all fish are potent swimmers, and they will become tired and lethargic whenever the flow of water in their tanks is too heavy.

Check for sores, bulging eyes, white spots, fuzzy areas, tail rot, or another sign your fish may have an infection. This problem may be caused by fungal illness or bacterial infection in a fish.

Test other water parameters to check if everything is how it should be.

What can you do to help your sick fish?

A dirty tank is a significant contributor to any tropical fish disease. If your fish has a bacterial infection, you can take it to a separate hospital tank to keep it in and sterilize the other tank. Keep a fish emergency kit, have fish medication on hand is a bright idea.

Types of Fish Medication

Fish medicine can usually be found online, but look in your loyalty fish store if you don’t have the medication available.

Even if you have no idea what causes your fish to become sick over time, a drug like Melafix gives them a fighting chance.

If you do not find or are in doubt about which medicine to use, use salt or medications based on natural essential oils and proceed with good hygiene and partial water changes in the tank.

All possible causes

Understanding your Betta fish’s behavior might help determine when you must act. Let’s find some of the causes why the fish lay at the bottom of the tank.

Senior citizens

As the fish becomes older, he slows down and gets lethargic. You may notice that he’s getting tired more often.

When he ages, he can usually be found lying in either the plant or the bottom of the tank. It is vital to keep you on the cutting edge with the water changes and watch out for opportunistic diseases, aggressive tank mates, or anything that affects the old fish.


Now you know the main reasons & have got your answer for your query Why is my fish laying on the side?

Use the information explained here correctly and see the importance of keeping the maintenance and water change up to date. Keep your fish in large aquariums, with a good filter system perfectly sized and everything else that the species need, especially the parameters to live correctly.

Keep a first aid kit for fish prepared. Know that drastic water changes will affect your animal’s health and their lifetimes.