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Why Your Blue Tang Is Laying On Its Side!

With blue tang being one of the most popular marine fish kept within the fish keeping hobby due to their beautiful look and the Finding Dori movie, we often see beginners adding at least one Blue Tang to their tanks.

This can result in a wide range of questions from people new to keeping the species as they can be tricky to keep in some situations and one common question that we have seen people asking about recently is why their blue tang is laying on its side.

It can be a natural behavior for a blue tang to lay on its side as “playing dead” is a natural defense of blue tang as with some blue tang also sleeping or relaxing on their side in their tank when there is actually nothing wrong with the fish.

In some situations, your blue tang may be suffering from swim bladder disease and this can end up causing a number of problems with your fish with the fish laying on its side being one of the main symptoms.

Although swim bladder disease is a risk, the majority of cases of a blue tang laying on its side will simply be due to the fish relaxing, sleeping, or playing dead due to a perceived threat rather than swim bladder disease.

If you do suspect that your blue tang is suffering from swim bladder disease then there are a number of No products found. on the market that you are able to use to treat your Blue Tang.

Why Is My Blue Tang Laying On Its Side?

Blue tang do have some strange behaviors as far as fish go and laying on their side is considered a normal behavior for the species.

This does cause a number of people new to keeping blue tang to worry thinking that their fish has swim bladder disease when in fact there’s nothing wrong with the fish and it is simply relaxing on its side.

With blue tang being more susceptible to ich than other fish species, especially marine fish species, we have seen some people curious if a blue tang laying on its side could be a side effect of ich.

This is not the case and ich will usually not cause your blue tang to lay on its side due to ich being an external parasite but some internal parasites can sometimes cause your blue tang to lose control of buoyancy.

If your blue tang does have ich then our article going over how to treat a blue tang with ich may be worth reading as the species is usually difficult to treat when suffering from ich.

Some blue tang will always sleep and relax on their side where as others will change their sleeping position depending on the area of the tank where they sleep.

The water flow levels of your tank can also come into play with your blue tang laying on its side to sleep too with a tank that has higher water flow generally having a high chance of your blue tang and other tang species sleeping on their side.

Do Blue Tang Play Dead?

Blue tang can “play dead” and lay on their side when they feel threatened but this behavior is generally less common in a blue tang that has been bred in captivity than wild blue tang. Still, some blue tang kept in community tanks with multiple fish species can lay on their side to play dead with some fish staying in this position for long periods of time.

If you have any aggressive tank mates in your aquarium then this could be the reason that your blue tang is laying on its side as it may be being harassed by its tank mates.

Even if you only keep blue tang in your tank but your tank is too small for them then this could still be the problem.

Most tang species need a larger aquarium with stress and anxiety being common in blue tang that are kept in smaller tanks with this commonly resulting in aggression between the fish.

The younger or weaker blue tang in your aquarium may end up being the target of most of the aggression from your other blue tang in this situation.

Over time, this can cause the blue tang that is being harrassed to lay on its side for long periods of the day to try and discourage the aggressive attention of its tank mates.

If you do notice this type of problem in your tank then you really should be looking to upgrade to a larger tank as soon as possible.

Do Blue Tangs Sleep On Their Sides?

A small number of blue tangs will always sleep on their side no matter the conditions of their tank with this being a common reason that you may see your own blue tang on its side.

In some tank setups, the conditions can increase the chances of your blue tang sleeping on its side with high water flow often being the main factor that will cause a blue tang to sleep on its side rather than the verticle.

If you do have a particularly high water flow in your tank for a valid reason then this may just have to be something that you live with.

For the most part, a blue tang sleeping on its side due to water flow should not cause any issues with your fish provided it is not being pushed against an object in the tank that may cause it harm.

The majority of our readers will not need a high level of water flow that will be enough to cause their blue tang to sleep on its side when it would otherwise sleep upright though so this is rarely an issue.

Although it is definitely a minority of blue tang that will sleep on their side even in perfect conditions, it is common enough to be the cause that lots of people reaching out about their blue tang laying on its side will find that it is simply the way their fish naturally sleeps.

In this case, there is nothing to worry about and it can actually look cute to see your blue tang sleeping on its side.


That brings our article going over why your blue tang is laying on side to an end. We hope that we are able to help you understand that it is surprisingly common for a blue tang to lay on its side and the majority of the time, it is not due to swim bladder disease and that your fish will usually not need any special treatments to fix the situation.