Do Fish Yawn?

Photo of author
Written By Editorial Staff

Veterinary Experts

Do Fish Yawn? That is a question that has puzzled many fish keepers. The jury is still out on this one, but there are some interesting theories.

Fish breathe through their gills, so they don’t really have a need to yawn as we do. Yawning is thought to be a way to increase oxygen intake and blood flow to the brain. The movement made by fish by opening their mouth may have a resemblance to yawning but rest assured they are not yawning. It is their way of either attracting a mate or fending off a predator.

Do Fish Yawn?

Do Fish Yawn?
Do Fish Yawn?

No, fish do not yawn as humans do. They do open their mouth, and sometimes it looks like they are surely yawning, but it’s not. The movement fish make that looks like yawning is their way of attracting a mate or fending off a predator.

Fish have a very different respiratory system from humans. Humans take in oxygen and release carbon dioxide through their lungs. Fish, on the other hand, breathe using their gills. They take in water through their mouth and pass it over their gills, where the oxygen is extracted, and the carbon dioxide is released [Source: IOWADNR].

But I Saw My Fish Yawn!

Studies have shown that when fish are placed in stressful situations, they often open their mouths wide and inhale deeply. This is similar to the way humans yawn when they’re feeling stressed or tired.

Fish show some of the behavioral signs associated with yawning, such as opening their mouth wide for several seconds. However, there is no direct evidence that fish actually yawn. So the jury is still out on this one.

Why Is My Fish Opening Its Mouth?

There are a few reasons your fish might be opening its mouth. If you see your fish gasping frequently, it could be a sign of poor water quality or something more serious, like gill parasites. If you notice any other abnormal behavior, like lethargy or loss of appetite, take your fish to the vet for a check-up.

In some cases, fish open their mouths because they are trying to get rid of a bad taste. If you’ve recently fed your fish live food that was sick or dying, it’s possible your fish picked up a disease. If you think this might be the case, quarantine the affected fish and treat them with an anti-parasitic medication.

What Does It Mean When Fish Open Their Mouths?

When fish open their mouths, it can seem like strange and often worrisome behavior. However, there are actually several different reasons why fish might open their mouths, each of which is related to normal activities and processes within the body. For example, many types of fish feed by sucking up food into their mouth, so opening it may be a way for them to accommodate larger pieces of food better.

Additionally, when water passes over the gills of some species of fish, they will naturally open their mouths in order to let that water flow in more easily.

Finally, some species will periodically gape as a means of regulating gas levels or otherwise clearing out any blockages that may be causing discomfort or stress. So although it may look worrying at first glance, there are many perfectly natural and innocuous explanations for why fish might open their mouths. In fact, this behavior should be seen as an indication that all is well with the fish!

Why Does My Fish Open His Mouth And Yawns When He Sees Me?

There are a number of possible explanations for why your fish might open his mouth when you approach him. One possible reason is that he associates your presence with food, and so he reacts by opening his mouth in anticipation of getting a meal. Another possibility is that the sight of you triggers a fear response, causing him to feel anxious and thus open his mouth as part of instinctive calming behavior.

Additionally, it could be that he simply wants your attention, and so as a way to get noticed, he will open his mouth to draw your gaze towards him. Whatever the reason behind this behavior, it’s important to keep in mind that different fish may react differently to stimuli and that what works for one may not work for all.

Should I Be Worried If My Fish Looks Like It Is Yawning?

The short answer to this question is no – you should not be worried if your fish looks like it is yawning. This type of behavior is completely normal and often occurs when a fish is getting ready to swim or feed. Some fish, such as goldfish, may even gape more frequently than others. So if you see your fish opening its mouth from time to time, there is no need for concern.

Sometimes this behavior may simply indicate that the fish is tired and needs to rest. In other cases, it could be a sign that the environment in your aquarium is causing stress or anxiety for your fish. To determine if it is something to worry about, you should look at the overall health and behavior of your fish. If they appear energetic and healthy, then an open mouth may simply be a normal part of their day-to-day routine. However, if they seem lethargic or display other unusual behaviors as well, you should take steps to remedy the situation to ensure that your fish remains happy and healthy.

Just remember to keep the water in your aquarium clean and well-oxygenated, and feed your fish a healthy, varied diet for best results.


So there you have it – everything you need to know about fish and yawning. Do fish yawn? No, not in the traditional sense. However, they may open their mouths wide for a variety of reasons, including feeding, gas exchange, or simply to get your attention. If you see your fish gaping from time to time, don’t be alarmed – this type of behavior is perfectly normal. Just be sure to keep an eye on your fish’s overall health and behavior, and create a comfortable environment for them to live in, and you’ll be sure to have happy and healthy fish for years to come! Thanks for reading!

Was this article helpful?