Why is my Clownfish Laying on its Side? {Are They Sick}

Are you seeing your clownfish laying on its side and getting worried?

Should you be worried about a disease or is this normal?

If you think it’s fishy behavior, then we should take a deeper look.

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Clownfish act silly in aquariums and that’s part of the reason why we enjoy them. They enjoy the mating process and sometimes play games together. If one clownfish is laying on its side for a short period of time, don’t worry!

If the action persists and you notice them slowing down, then maybe it’s a sign of a disease. The best thing we can do at first is to watch carefully and be patient. If there’s a problem, then we should notice more than just laying on its side.

Why is my Clownfish Laying on its Side

Why is my Clownfish Breathing Heavily?

Now, we’re looking closer and noticing heavy breathing patterns in our clownfish. What is happening? Well, the most popular answer is that something may be impacted or stuck in their gills.

Is the clownfish being chased around by its mate or another species of fish? A clownfish could be experiencing stress and rapidly trying to get away. This would cause heavy breathing.

It’s also important to inspect the ph levels to make sure it’s between 7.8-8.4. Also test the water for high nitrate and ammonia levels. All these factors could cause heavy breathing.

A clownfish that has just been transported into a new tank of water may also breathe rapidly. This may stop soon, so just pay attention and see if it persists. Finally, a quick freshwater dip might help clean out their gills.

Why is my Clownfish Laying on its Side?

We keep looking and nothing is changing. The clownfish is still laying on its side. Could it be something worse? It’s time to look at the worst case scenarios.

Brooklynella disease is common in clownfish. It’s parasitic and deadly. It attacks the gills and makes it hard for the clownfish to breathe. In time, the clownfish may lay on its side and slowly die. This is awful news, but we have to be prepared for this case.

Formalin is a solution that dissolves in the water with methanol to help treat Brooklynella disease. Look into this and have some handy if your clownfish keeps laying on its side.

Swim bladder disease could also be the culprit. The bladder fills with air or gas and causes the clownfish to swim on its side.  If your clownfish is not swimming and only laying on its side, then it probably isn’t swim bladder disease.

Is my Clownfish Playing Dead?

Keep in mind that clownfish are silly sometimes. Your clownfish could be playing dead. Male clownfish act funny when they’re trying to convince their female suitor to become their mate. Frantic movements or playing dead are part of their game sometimes.

Clownfish also sleep on their side and this is quite normal. If they spring back into action when they’re up and about, then there’s no need to worry. This is more common for clownfish in captivity and less frequent for wild clownfish.

Sometimes shining a light like a torch or allowing the sunlight to shine on them helps. If you want to see if they are just playing or sleeping, try the light test. If they get up and start moving normally, everything is fine.

 Why is my Clownfish Laying on Rocks?

Clownfish may lay on rocks when they decide they want to call that spot for their own. They might be protecting the territory. If there is no anemone hosting the clownfish, this may be even more common.

Sometimes clownfish do this when it’s dark. If they continue laying on rocks while there is some daylight, they might be protecting eggs. Look closely and see if that’s the case.

A sluggish or lethargic clownfish laying on the rocks may be having difficulty breathing. This is when you may have to clean out the water. Always test: PH, salinity, nitrate and ammonia levels if you’re concerned. Keep the following information in mind:

  • 29 gallons or 130 liters or water
  • Salinity level of 1.020-1.025
  • 72-78°F or 22-26°C water temperature
  • Check water quality once a week
  • Change the volume of water every 2 to 4 weeks at least 10-25%
  • Add anemone, vegetation or rocks

Why is my Female Clownfish Laying on its Side?

The female clownfish is more dominant. They could be dormant and watching the male perform for them during the mating ritual. This may not be the case however.

The female clownfish may be pregnant or trying to get her eggs out. Watch and see. In most cases, the water is the issue and a large water change might be necessary.


We buy fish and enjoy watching them. Sometimes it’s important to watch closely and observe any strange behavior like a clownfish laying on its side for far too long. Before trying to diagnose any illnesses, the aquarium itself needs to be tested.

Removing the clownfish from the aquarium and placing them temporarily in another tank may help. Look carefully to see if they are breathing with their gills being obstructed. Look, test, wait and clean their space.

We wish you the best of luck and check out more of our guides on clownfish.



Hello, I'm Jason. I'm the guy behind HelpUsFish.com. I volunteer at my local fish shop and I created this site to offer tips and advice on the fish I care for.