7 Reasons Why Do Fish Jump out Of Tank

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If you house several fish species in your freshwater tank, you may have witnessed them jumping out of their tank. In their natural environment, fish often dive to get away from danger and move to a different area.

But, if your pet fish try to do the same in their tank, they will fall on the ground. It is obviously not optimal because your fish can not stay longer without water and will eventually die.

Some fish parents may believe that such jumping activities are quite common in some aquatic species, but they are wrong. Diving is a protective strategy used to escape attackers and undesirable water parameters.

why do fish jump out of tank

Insufficient amount of oxygen causes aquatic animals to escape from their tanks. Likewise, when the water contains an excessive amount of nitrates and ammonium, they will definitely try to run away.

Other contributing factors involve irregular sleeping patterns, a tiny aquarium, infections, illnesses, and an absence of places to hide. Diving happens naturally in certain species.

You will have to make the tank’s environment better if you want to stop aquatic animals from leaping out. Fortunately, there are a number of techniques you could follow to achieve this, and your pet would live in a healthy, peaceful environment.

7 Reasons Why Fish Jump Out Of Their Tank

1. Overcrowding

Overcrowding Fish Tank

Fish are big fans of open spaces. If you house them in a tiny and overcrowded tank, they will try to escape their home. In order to avoid this situation, you should provide them with a large tank that has plenty of space to swim around freely.

Fish find it difficult when they can’t swim properly. Species being mistreated or abused will often escape from the tank to run away from the bully fish if they don’t find the space to hide.

You should house a limited number of aquatic species, give plenty of hidden spots, and include lots of strong plants and bushes in your tank to give them a homely feel and security.

2. Insufficient Oxygen

The absence of soluble oxygen in the freshwater tank is among the main factors of fish fleeing outside from tanks in search of new homes. Although the majority of species lack lungs to inhale atmospheric oxygen, they still need soluble oxygen inside their aquarium to survive.

Fish may dive outside the tank water in an effort to reach a spot with more soluble oxygen if they are unable to live a healthier lifestyle. There are various causes for an oxygen shortage in the aquarium.

If you have an overcrowded aquarium, then naturally there would be a lack of soluble oxygen. Every species will end up struggling and finding a source of oxygen to survive.

Reduce the number of species in the same-sized aquarium or invest in a larger water aquarium to fix this problem. If you don’t want to undertake any of these actions, you can install an air bubbler on one of the tank corners.

In order to provide fish with sufficient soluble oxygen to survive, air bubblers are used to ventilate and detoxify the water.

Algal growth may also be a concern. Also, under correct circumstances, algae may be problematic because they can consume a considerable level of oxygen.

If your aquatic species are hopping away from the aquarium and you detect an algae growth, it’s possible that the fungus is taking up all the oxygen. As a result, in order to provide your pet with a healthy environment, you will have to eliminate fungus from their aquarium.

Also Read: Can Fish Drown?

3. Toxic Level of Ammonium and Nitrite in The Tank Water

High levels of chlorine, nitrites, and contaminants in the home aquarium are also a factor that might force your pet to get out of its habitat. Therefore, your pet fish may try to escape if the surroundings or water purity are not optimum in quest of a healthier environment.

Even small concentrations of ammonium may affect marine life and cause them to become seriously ill, which is a major concern. You should invest in a water testing kit and check your tank’s water condition to see if it is safe for your pet.

You understand that there is a risk if the concentrations are even slightly higher than the advised limit, even though in this scenario is 0%. Excessive ammonia concentrations are often triggered by decomposing substances like biowaste, leftover food, dead animals, and rotting vegetation.

As a result, conducting routine water replacements, avoiding overfeeding your species, frequently removing litter and dirt, and constantly ensuring that the tank environment is as fresh and sanitary as possible are a few methods to reduce ammonium.

Having a reliable biological filtering system installed is also crucial. Biological filtering medium decomposes ammonium and makes it safe.

You would have to face a major loss if you have not installed a filtration system or if it isn’t functioning correctly. Ensure that your biological filtration system is in good working condition.

A clean filter should always be used, and it should be replaced if required. Additionally, providing a supplement with good microorganisms can be helpful. Healthy bacterias are good for your pet’s health and improve their overall immunity and activity levels.

4. Unacceptable Water Parameters

The majority of freshwater aquatic animals are highly vulnerable to sudden water changes in their home tank. If your fish finds the water temperature extremely hot or freezing, then it decides to escape from this unsuitable environment.

Generally, you may quickly solve this matter by ensuring that the water conditions are optimal for your freshwater species.

By placing the heating rod near the outlet of the biofilter motor, you may guarantee that the water temperature is uniform everywhere in the aquarium. It’s going to be the most effective way to distribute hot water throughout the aquarium.

Set up two tank thermometers: one near the heating rod and the second quite far away towards the opposite direction so that you can ensure that the water temperature is consistent throughout the tank.

5. Bullying

Some aquatic organisms have strong territorial impulses and struggle to socialize with their tank mates.

Housing a species that is unfit for shared aquariums may result in conflicts, tail nipping, and extreme bullying, forcing your shy fish to jump outside their aquarium.

6. Stress

Fish housed in extreme situations with lots of stress factors would get overtired and attempt to leave the aquarium.

Your pet will get upset due to the noise level, strong artificial light above the aquarium, flickering lights for a while, continuous light throughout the night, and changing tank position inside the house.

7. Lack of Hiding Spots

Aquatic species love dense plantations to hide, play around, and snooze inside their home tank. They help small species avoid danger by acting as protection from bigger, more aggressive fish.

Some animals feel scared and unprotected when there aren’t sufficient places to hide. Additionally, they might experience anxiety which is not good for their health.

All of this does not end well for your fish, and they have no other option other than jumping out of the tank.

How Can You Prevent Your Fish from Jumping out Of the Aquarium?

Glass Tank Covers

Fiberglass tank covers or caps are basic items that are available at almost any aquarium dealer. They usually include a lid that makes it simple to quickly pull up the top part in order to reach inside the aquarium and feed the fish.

They are available in pre-set sizes to fit all sorts of popular, edged tanks. Some of the tanks come with their lid, so you won’t have to buy them separately.

Floating Plantation

Fish will be less likely to escape if there are lots of floating leaves, shrubs, and plants occupying the surface of the tank. With a surface full of green plants, they can prevent the fish from jumping out to a great extent. However, your pet may still escape if its surroundings aren’t right.

Duckweed is preferred by marine enthusiasts over Salvinia, although any plant works effectively. Additionally, aquatic contaminants like ammonium, nitrite, and nitric, as well as toxic pollutants that could make your fish ill, are significantly reduced by floating vegetation.

Get a Tall Aquarium

Having a tall aquarium could also prevent your fish from going to the surface. Even if they need to escape from any bullies or just want to dive around, they could make higher jumps in a much safer way inside a tall tank.

Decrease the Tank Water Level

In most cases, your pet fish finds it easier to jump if the tank water level is quite high. You can make it difficult for them by decreasing the water level by 5-6 inches down. Of course, you must consider your overall tank volume, dimensions, and shape before trying this technique.

It is also not appropriate for every fish as some of them want a higher level of the water as compared to the rest. You should consider these factors before making any changes to their home.

Pick Compatible Tankmates

You can save your pet’s life by housing it with species that are friendly and peaceful. Try to avoid aggressive species as it will only create chaos in your pet’s life, and it could be stressful and tiring for them to be chased and bullied by their tank mates.

You must first find out if your chosen fish get along with other species in an aquarium by conducting research on them. Try to house the same species together or their close cousins as they share similar temperaments and water conditions. They would love each other’s company, and it would maintain a harmonious environment in the tank.

Soundproof Room or Low Noise Level

Sound waves can travel a lot faster, around 4 times, than it does in air. Therefore, persistent, loud music upsets fish, leaving them to become anxious and restless. They try to escape from these strong sound waves in their tank by jumping outside and giving up on their lives.

Make sure your species are kept in a peaceful, calm environment to avoid this. You should turn off your electronic devices like television, speakers, laptops, and virtual assistant technology systems if placed near your aquarium.

Provide Sunset and Sunrise Lighting

Aquatic animals in the sea are never exposed to a quick transition from brightness to complete darkness. Your pet may get startled and start to find a hiding spot or simply escape from the tank if this happens.

To imitate the normal sunset and sunrise timings, schedule your artificial lights in order to create a slow change from night to day and vice-versa. Additionally, try to avoid entering the room at the night and switching on the lights.

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How High Can a Fish Jump?

The majority of freshwater fish are able to dive a few centimeters above the water surface before falling out from the aquarium. Species such as betta can go up to 2-3 inches above the water’s surface.

Among the best freshwater fish like hatchet can make a jump of 5 feet, which is stunning.

Can Ich Cause Your Fish to Jump out Of a Tank?

In an effort to relieve the itchiness brought on by epidermis parasites like Ich, species may flick and brush against the plant stems, gravel, and tank ornaments.

Therefore, it’s possible that many such animals dive for this reason. To get your pet fish back to being peaceful in the aquarium, regularly check them for infections and provide effective treatments to them as necessary.


As you’ve seen, there could be a lot of potential factors for your pet to escape from their aquariums.

In such a situation, you must monitor the species, see if the tank is the right fit for them, check that your filtration system is in good working condition, evaluate the water for toxic components, and manage the water’s ph.

Finding the root cause is the only way you can save your aquatic species from falling on the floor. It could be a long process for beginners, but after learning and understanding their needs, you would be able to provide the best environment for these lovely creatures.

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