Why do fish jump out of tank (And how to stop them)

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by Jason Matthews



If you love fish and keep an aquarium, one of the things that you will notice is that fish try to jump out of the tank. This can be worrisome as you may wonder why they are doing this, especially when they have a nicely decorated and safe home. Well, there are many reasons for this. 

Fish often behave strangely when they feel stressed, sick, or threatened; one of these behaviors is jumping out of the fish tank. It is important to remember that your fish are confined in the fish tank, and they do not realize this. While it is an instinct to jump out of the fish tank, it is primarily because the water conditions you have provided in the tank are unsuitable. However, it could be an accident, or your family cat may have posed a threat. 

Let us explore the different reasons that cause fish to jump out of a fish tank to their death and what measures you can take to prevent this from happening. 

Why Do Fish Jump Out of the Tank?

While there are numerous reasons why fish jump out of the fish tank, we have narrowed it down to the most obvious and common reasons. 

  • Food: Though this does not happen very often, fish can jump out of the fish tank to capture food. For instance, if they see a fly or mosquito hovering around, they may try to catch and devour it. 
  • Poor Quality of Water: If you don’t clean the tank regularly, the water quality will deteriorate. This will cause your fish to jump out in search of better water conditions. They do not know that doing this will lead to them dying. This jumping is more of a survival instinct. 
  • Lack of Oxygen: In case the water in the tank is not properly oxygenated, the fish’s natural reaction would be to try and escape so that they find better living conditions. Remember, the fish will feel suffocated if there is low oxygen content in the water and will jump out. 
  • Predators: If you have a cat at home, it will be fascinated by the colorful fish you keep. These small fish will feel threatened by the cat and try to escape, so they are not eaten. Jumping out of the fish tank is the reaction they demonstrate. 
  • Accident: Sometimes, even when you maintain the fish tank well and look after your fish, you may come home and find one of your fish lying dead on the floor. Some fish swim fast near the surface of the water, which can cause them to jump out of the water accidentally. 
  • Stress: Just like humans get stressed, fish too experience it. According to fish lovers and experts, this is one of the biggest reasons for fish jumping out of the aquarium. Stress can be caused due to poor water conditions, predators, diet, or any other issue. 
  • Incorrect Water Temperature: If you do not monitor and maintain the right water temperature in your fish tank, fish will jump out in search of water that has the right temperature. 

Many tropical fish are prone to jumping out of the fish tank. Usually, it has been observed that fish that spend a lot of time swimming at or close to the surface tend to jump out of the tank.

Some of the fish that tend to jump out are as follows:

  • A majority of top dwellers
  • Most fish that swim fast
  • Hatchet 
  • Betta
  • Rainbowfish
  • Tetra (though not all)

How to Stop Fish from Jumping Out of the Tank

Here are a few measures that you can take to ensure that your fish do not jump out of the aquarium. 

Method 1: Install an Aquarium Lid

Rather than risking the fish jumping to death, get an aquarium lid and install it. The lid comes with hinges that allow you to lift it so you can feed the fish and access the tank while cleaning it. Premade lids are available in different sizes for rimmed aquaria. 

For a rimless aquarium, you can get a custom-cut glass or acrylic piece and use a kit to ensure you can attach the light fixture and other fittings to the lid without a problem. 

Method 2: Introduce Floating Plants

Another method to stop fish from jumping out of the fish tank is to have a lot of floating plants in the tank. 

Although this is not a 100% foolproof method, it is more effective than not having anything. The floating plants create a visual barrier that prevents fish from jumping out. 

Use plants like duckweed and Salvinia in your fish tank. Besides preventing the fish from jumping out, these floating plants also reduce the content of heavy metals, ammonia, nitrate, nitrite, and other toxins in the water. 

Method 3: Lower the Level of the Water

Depending on the size of the fish tank and the kind of decoration you have in the tank, you can think about lowering the water level by a few inches. Since the water level will be slightly low, it will be more difficult for the fish to jump out. 

Reducing the water level will not deter them from jumping, but it will prevent the fish from escaping out of the tank. This method tends to work well with fish tanks that do not require a full volume of water. Ensure that the tank has sufficient water for the fish and the aquascape you have installed.

Now you know why fish jump out of the tank. It is prudent to remember that fish will try to jump out as it is a behavioral instinct. Hence, you should endeavor to prevent your fish from doing it. You should use a combination of preventive methods to stop your fish from jumping out of the tank.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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