Why Is My Clownfish Laying On The Bottom? (With 5 Solutions)

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It can be a frustrating experience when your clownfish insists on staying at the bottom of the tank. I remember when I first bought my clownfish, the little guy kept diving to the bottom of the tank over and over again. Luckily, as time passed, I learned why this was happening.

Clownfish tend to lay on the bottom of the tank due to inappropriate water parameters, including elevated ammonia, oxygen deficiencies, and high temperatures. However, in some cases, the clownfish will stay at the bottom merely because it is sleeping or taking care of hidden eggs.

As we move forward, I will share why and how to get your clownfish to leave its spot at the bottom of the tank. I will also present a helpful video to help you take care of a potentially sick clownfish carrying a parasitic infection.

Also Read: Clownfish Care Guide

Why Is My Clownfish Staying At The Bottom Of The Tank?

The first question you should ask yourself is whether your clownfish is dead. Don’t assume that the creature is lying peacefully at the bottom. Try prodding it. If that doesn’t work, lift it out of the tank. 

The gills on a dead fish are still because it has stopped breathing. You should also look for sunken eyes and cloudy pupils.[1] If the clownfish is dead, remove it from the tank before it rots. 

If the clownfish is alive, look for signs of one or more of the following:

1. Your Clownfish Is Attracted To Its Anemone

Is your clownfish lying directly on the substrate, or is it hovering within the tentacles of an anemone? Anemones are relatively dangerous. Their tentacles will sting any fish that gets too close. 

However, clownfish can swim safely within these tentacles. The pair have a symbiotic relationship.[2] Clownfish prefer to sleep inside anemones because of the security their presence provides. 

If you have an anemone at the bottom, the clownfish’s decision to remain within the vicinity of the anemone shouldn’t surprise you. That is especially true if your clownfish is sick or stressed. 

2. The Clownfish Is Taking Care Of Eggs

Female clownfish will lay eggs, but they won’t care for them. That responsibility falls on the shoulders of the males. They will fertilize, clean, and protect the eggs.[3]

Clownfish will find a bare rock near an anemone to lay their eggs. But if you don’t have anemones in your tank, they will make do with any secure spot they can identify. 

If the male clownfish have limited their movements to a specific location on the substrate, look for eggs. The female can lay anywhere between a hundred and a thousand eggs.[4]

3. Your Clownfish Is Sick

Like humans, diseased fish are less active. Any severe illness can strip a clownfish of its strength. The creature will spend most hours of the day or night resting on any safe surface it can find, including the substrate. Two illnesses stand out:

  • Brooklynella

This disease attacks the gills of marine fish. Caused by Brooklynella hostiles, clownfish with this illness are easy to spot because they scrape against objects. You can’t confuse their symptoms for ich because they don’t have white spots.

Once mucus clogs their gills, they become lethargic, lying at the bottom of the tank while gasping for air. Eventually, a thick white mucus will cover the body. 

  • Swim Bladder Disease

Swim bladder disease affects the swim bladder. Caused by bacterial and parasitic infections, physical injuries, constipation, and genetic anomalies, swim bladder disease compromises a clownfish’s swimming ability.

The consequences will vary. Some fish will swim on their sides, while others will swim upside down. You also have those who won’t swim, especially if the swim bladder disease is accompanied by extreme bloating.

4. The Clownfish Is Merely Sleeping

Clownfish can either rest or sleep by lying at the bottom of the aquarium. If you have anemones, the clownfish will sleep inside the anemones. If you don’t, they can make do with the substrate.

They are more likely to sleep at night, especially if the lights are off. But if you introduce substantial stimuli, they will wake up. For instance, you can turn the lights back on or disturb the water with your hand. If the fish responds, it is merely sleeping.

Clownfish shouldn’t sleep all the time. If you created a proper day/night cycle, the fish would sleep at night when the lights are off. They can occasionally sleep during the day. But they shouldn’t make this a habit. If your clownfish are always asleep, something has gone wrong. More than likely, they are sick.

5. The Environment Isn’t Suitable For Clownfish

You have four major factors to consider where the behavior of your fish is concerned:

  • High Ammonia Levels

If the clownish is gasping for breath at the bottom, don’t be so quick to blame brooklynella. Brooklynella attacks the gills, but so does ammonia. The toxic substance poisons fish, not only compromising their ability to breathe but also weakening their immunity.

Nitrates are less potent than ammonia, but they are toxic to clownfish as well. In both cases, the affected fish will become lethargic. If the ammonia and nitrate levels remain dangerously high, the clownfish will die.

  • Oxygen Deficiency

An oxygen deficiency is a situation where the clownfish doesn’t have enough oxygen. You would expect an oxygen deficiency to send clownfish to the surface where the oxygen levels are rich.

However, if a temperature spike causes oxygen deficiency, the clownfish are just as likely to run to the bottom. This is because cool water holds more oxygen than warm water. 

In a hot tank, the bottom is the coolest section, which means that it has one of the highest oxygen concentrations in the tank. The clownfish will stay at the bottom until the oxygen levels above improve or until the oxygen content at the bottom falls to dangerous levels.

  • Inappropriate Water Parameters

The wrong parameters expose clownfish to stress and diseases. This is also true for unstable parameters, including a rapidly changing temperature and pH.  

  • Overcrowded Conditions

Some clownfish run to the bottom because they don’t have room to maneuver in the aquarium. At 6 inches, clownfish need at least 20 gallons to thrive. An overcrowded tank that has too many fish will force them to the top or bottom.

How To Treat Clownfish That Stay At The Bottom?

Once you identify the source of this behavior, it won’t take long to locate a suitable solution. Your options include:

1. Adjust The Environment To Clownfish

I suggest maintaining a pH of 7.8-8.4 and a temperature of 74 to 79 degrees F.[5] Keep these parameters stable. If you have the wrong temperature or pH, alter these parameters gradually until you reach the appropriate range.

I also recommend keeping the ammonia, nitrates, and nitrites and 0 ppm. I personally use the API Water Test Kit (link to Amazon) to measure these parameters. That bundle lasts for about eight hundred measures, making it highly cost-effective.

Keep an eye on the population. If the tank is too small to house all your fish, you can either get a bigger tank or remove some fish. The tankmates are just as important as the size of the tank.

The wrong tankmates will antagonize your clownfish regardless of the size of the tank. Suitable tankmates include butterflyfish, damselfish, and harlequin shrimp. Avoid large, aggressive fish like saltwater Angelfish. 

2. Take Care Of Sick Clownfish

Swim bladder disease and brooklynella have numerous treatment options. For instance, the same solutions that fight other parasitic infections can treat brooklynella. 

That includes malachite green, copper, chloroquine, and formalin. If you have ever treated your fish for ich, the same remedies can alleviate the symptoms of brooklynella. As described in the following video, a 37% Formaldehyde solution is also likely to work:

With swim bladder disease, the cause will influence the solution. If the swim bladder was injured by physical trauma, the clownfish would heal on its own, especially if it had favorable conditions in the tank.

If bacterial and parasitic infections wound the swim bladder, you have to match the remedy to the infection. If constipation caused the ailment, a regimen that includes a 3-day fast and a diet of cooked and peeled peas would improve the clownfish’s health.

You may have to place the fish in quarantine, especially in cases where you haven’t identified the disease ailing the creature. If you can improve the clownfish’s health, it will abandon its habit of lying still at the bottom.

3. Conduct Regular Water Changes

You cannot treat diseases and infections by simply adding antibiotics to the tank. You have to keep the water clean. In fact, most aquarists expect you to respond to diseases and infections by carrying out an immediate water change.

But you have to treat the new water with conditioners to prevent toxins like chloramine from doing more harm. Don’t stop performing water changes simply because the clownfish’s condition improved. Change the water (15 percent) every week to prevent these issues from returning. 

4. Elevate The Oxygen Concentration

Besides keeping the water clean, an under-gravel filter will agitate the water, preventing it from stagnating. Stagnant water is susceptible to oxygen deficiencies. Larger aquariums require powerful pumps that can agitate the water sufficiently. 

If you don’t want to buy a more powerful filter, consider an air stone. I personally got the Hygger Aquarium Air Stone Kit (link to Amazon). It is impressively quiet and gets the job done. All you have to do is place it in the middle of your tank.

During emergencies, where the fish are clearly distressed because of an oxygen deficiency, perform a large water change. Along with agitating the water, the new water will add oxygen to the tank.

5. Get Rid Of Ammonia

You can combat ammonia by changing the water every week and removing dead organisms. If you don’t have the time to perform a water change, add water conditioners. They will neutralize the toxins, buying you the time needed to change the water and clean the tank.

I usually use the Seachem Prime Conditioner (link to Amazon). That product will ensure ammonia, as well as other toxins, never spike in your tank. If you are new to this, here is an article where I discussed how to use water conditioners.

If you have a habit of overfeeding your clownfish, stop it. Excess food leads to excess waste. That waste will rot, creating more ammonia. Feed your fish the amount they can finish within two to three minutes.

In that same vein, if you think your clownfish are dead, use a net to take them out of the tank. Living fish will react to this transition. Dead fish will remain still.

Will Clownfish Eat Off The Bottom?

Clownfish will eat food from the bottom. Technically speaking, they will eat the food wherever they can find it. They will hunt for it throughout the tank if the need arises. That includes the tank’s bottom, between leaves, and even inside anemone tentacles.

However, this doesn’t apply to every single clownfish. Many aquarists expect their clownfish to eat the food before it hits the bottom. You won’t know how your clownfish will respond until you test them. They will either scavenge for food at the bottom or ignore it.

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Clownfish usually stay at the bottom of the tank because of environmental factors, such as temperature, ammonia, and pH imbalances. These issues also hamper their energy and activity levels.

That’s why it is critical to maintain an ideal environment in your clownfish tank. Ensure the temperature is within 23-26°C (74-79°F), keep ammonia and nitrites at 0 ppm, and keep the pH between 7.8 and 8.4.

I also suggest looking for hidden eggs. It is very likely that your clownfish hovers at the bottom because it is taking care of its future newborns. You should also consider that your clownfish is sleeping. If it does, it will react to stimuli.


  1. https://www.wikihow.com/Tell-if-Your-Fish-Is-Dead
  2. https://www.nationalgeographic.com/science/article/clownfish-help-their-anemones-to-breathe-at-night
  3. https://www.saltwateraquariumblog.com/clownfish-eggs-development-clownfish-breeding-journal/
  4. https://www.livescience.com/55399-clownfish.html
  5. https://www.fishkeepingworld.com/clownfish/