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Why Your Clownfish Is Staying At The Top Of The Tank!

Ever since the release of finding nemo, the popularity of clownfish has been increasing with each year that goes by as more and more people add at least one clownfish to their tanks.

With clownfish being a somewhat peculiar fish species with a number of quirks, we do often see people from the fish keeping community reaching out and asking why their clownfish is staying at the top of its tank so we wanted to publish this article to help our readers who keep clownfish in their own tanks.

In some situations, it can be normal for a clownfish to stay near the top of its tank or even right on the surface of the water but this is usually rare.

If the dissolved oxygen levels in the water of the tank are low then it can cause some clownfish to seek oxygen at the top of their tanks with this usually being something that is pretty easy to fix.

If you are keeping three or more clownfish in your tank then a single clownfish randomly starting to stay near the top of the tank can be due to clownfish aggression from the other clownfish who have paired.

This is often due to the paired clownfish nipping and chasing the third clownfish in their tank due to seeing it as a threat and you may have to move your third clownfish to its own tank to prevent these issues.

Is It Normal For A Clownfish To Stay At The Top Of Its Tank?

It is not considered normal for most clownfish to stay near the top of their tank but in some situations, a clownfish may take to hanging out near the surface of its tank due to a number of reasons.

This may be due to your clownfish choosing to host that area of your tank due to a lack of a suitable anemone, low oxygen levels in your tank water, aggression from its tank mates forcing the clownfish there, or the clownfish seeking food.

With so many people who keep clownfish being new to the fish keeping hobby it can be common for people not to realize that clownfish will often do better with an anemone in their tank for them to host.

We have a dedicated article going over the best anemones for clownfish that may be helpful but once the clownfish bonds with an anemone or fake anemone it will usually use that as the base of its territory.

As we covered in our article on why clownfish yawn and the one on why clownfish breath fast, a lack of oxygen in the tank can be a reason that your clownfish will stay near the top of its tank as it is trying to find water with higher amounts of dissolved oxygen.

This is usually a sign of serious water issues in your tank that need to be corrected as soon as possible as it poses a risk to everything in your tank, not just your clownfish.

How Can I Stop My Clownfish Staying Near The Surface Of Its Tank?

Depending on why your clownfish stays near the surface of its tank, it can be difficult to discourage the behavior.

If your clownfish is looking for food or areas of the tank with more dissolved oxygen in the water then correcting the issue can cause your clownfish to return to normal.

If your clownfish is staying near the surface of its tank due to hosting that area of the tank then it is very difficult to change the behavior once developed.

This is due to hosting being an instinctual part of the behavior of clownfish that is usually done with the clownfish it partners with as a way to build up its territory to start mating.

Once a clownfish has chosen something to host, even adding a better option such as a suitable anemone to the tank may not prevent the behavior.

We covered this in our article on clownfish swimming vertically due to hosting behavior with it being notorious to discourage once it has developed in your clownfish.

As we mentioned earlier in the article, smaller sub-forty gallon tanks with multiple clownfish in them can have problems with non-paired clownfish acting strangely and staying near the surface of the water to avoid aggression from the paired up clownfish.

Upgrading to a larger aquarium or moving the non-paired clownfish to their own tank is usually the best option in this situation as it is unlikely that the aggression will stop if things stay the same.

Should I Be Worried If My Clownfish I Staying Near The Top Of Its Tank?

For the most part, there is usually no need to worry about a clownfish staying near the top of its tank as it can be one of the quirks of your clownfish personality.

Even the less serious causes of this behavior in clownfish such as a lack of dissolved oxygen in the water of your clownfish looking for food are usually not a cause to worry due to being easy to fix.

If you have multiple clownfish in your tank then you can often rule most of the potential causes of the behavior out if only one of your clownfish is staying close to the surface of the water while the others act normal.

This suggests that there is plenty of oxygen in the water with plenty of food being available due to the normal behavior of the other clownfish and that this is probably down to the clownfish being bullied by its tank mates.

We have seen people reporting that a clownfish in a small tank will often stay close to the top of its tank but the most common symptom of a clownfish in a small tank is just a lack of movement.

A quick google check for the specific species of clownfish that you keep and the recommended minimum tank size for it should be able to correct this potential problem though as different clownfish species do require different minimum tank sizes.


That brings our article going over why your clownfish may be staying at the top of its tank to an end and we hope that you have found it helpful. Although there are a number of potential causes of this behaviour in your clownfish, the most common does tend to be due to the various quirks in the personality of many clownfish making them a particularly peculiar species of fish to keep that just do random things every now and then.