Fish staying at top of tank what to do? 

Fish, after a water change, under strenuous breathing, or difficult movement can sometimes come up to the water’s surface. This article will cover the concern “Fish staying at top of tank what to do?”, the reasons behind it, their solutions, etc.  

Fish staying at top of tank what to do?

Fish stay at top of the water tank because of shock after a water change, low amount of oxygen, and high levels of ammonia. Sometimes, the fish owners are sensitive towards their fish, and when they start staying up at the water’s surface, they become suspicious about this condition. 

Most of the time, there’s no need to worry if your fish is spending longer durations staying at top of the aquarium water, but sometimes, it happens because of a specific reason, and the only solution to this is addressing the problem and eradicating it. 

What are the reasons and their solutions if your fish stays at top of the tank? 

Following is the list of reasons associated with the condition if your fish is staying at top of the water tank: 

1. Insufficient oxygen 

Oxygen deficiency is one of the main factors that can make your fish stay at top of the water tank. As the oxygen level is high in the top water, the fish tend to swim to the top of the tank. Little movement of water, the rising temperature, and the overcrowded tank can be the reason behind oxygen deficiency in the tank. 


First of all, you’ve to alter your tank’s filter current. Aiming the filter in such a way that it disturbs the water surface more will increase the amount of oxygen entering the water. It’s one of the best short-term solutions for oxygen deficiency. 

However, some other methods can be used to tackle oxygen deficiency. For example, you can achieve it by creating an air bubble in the tank or adding live plants to the tank. Adding live plants will increase oxygen levels and decrease CO2 levels. 

2. Water temperature 

The lower temperature of the deep water also causes your fish to stay at the top of the water tank where the water temperature is warm. The water temperature can be a real problem for aquarists. 


If your tank is attached to a heater, the first step is to move the heater away so that it doesn’t create a temperature difference in the water levels. Doing this will maintain an equal amount of heat supply across all the water. 

3. Swim bladder disease

When fish are suffering from swim bladder disease, they frequently struggle to maintain their position in the water tank. Sometimes, they sink to the bottom of the tank, swim sideways, or float to the top of the tank. 


Swim bladder disease is mostly caused by constipation and overeating. To refrain your fish from staying at top of the tank, you’ll have to treat them for constipation. It can be achieved most easily by fasting your fish for a few days. 

4. Overcrowded tank 

An overcrowded tank can also cause your fish to stay at top of the tank. Overcrowded tanks not only have dirty water but also cause the oxygen level to drop faster. As a result of this, fish try to inhabit either the top or bottom of the tank, staying away from the other fish. 


You can solve this condition by removing the bully fish, which are more aggressive, and pushing away the other fish to the top of the tank. Moreover, you can add plants to compensate for the oxygen. The addition of hiding spots like driftwood, stones, or ornaments in the tank can also give your fish spaces to hide.  

5. High ammonia levels 

Too high ammonia levels can result in the condition of your fish staying at the top of the tank. Even if the tank water looks clean, the ammonia, nitrite, and nitrate levels in it can be so high that they can cause ammonia poisoning in fish. 


You should test the water in your fish tank for ammonia, nitrates, and nitrites to make sure that the ammonia levels are not above 0 ppm, nitrite levels are at 0 ppm, and nitrate levels are below 20 ppm. It can also be achieved by performing a water change. 

However, adding an ammonia neutralizer can reduce the number of nitrogen bodies in the water of your fish tank. The addition of ammonia removal media in the tank water can also reduce the overall amount of ammonia in the tank. 

6. Your fish may be a surface-dwelling fish 

Some breeds of fish like to dwell in the top or surface water of the tank, which means they are surface swimmers. For example, fishes like bettas, zebra danios, guppies, and hatchet fish are those which can be seen at the surface of the water tank. 

7. Your fish may have learned to swim to the top of the tank 

Last but not least reason behind your fish staying at top of the water tank could be that your fish have learned to swim to the top of the water. Sometimes, fish become habitual to associating you or a light turning on with their dinner time. In such cases, fish may swim to the top of the tank since they are expecting food. 


Today, we covered the article “Fish staying at top of tank what to do?”, the reasons behind it, their solutions, etc. From the above discussion, it’s concluded that your fish stay at top of the tank because of the above-mentioned reasons and these problems can be solved as explained. 


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