Why do my fish stay at the top of the aquarium?

Your fish stay at the surface of your aquarium and you want to know if there is a problem? Naturally, aquarium fish evolve at different depths in the aquarium. Although some varieties prefer to stay at the bottom, others will appreciate the middle or upper regions.

However, if you notice that your fish are spending most of their time at the surface of the water, this could be a sign of an underlying problem. Of course, it is also possible that your fish are just begging for food, being big foodies.

A breathing problem

When fish stay close to the surface, it means that they are trying to breathe more easily. In fact, fish breathe thanks to the presence of their gills. These allow them to capture dissolved oxygen, without association with the H2O molecule. Dissolved oxygen levels are generally higher when approaching the surface, because there is an interaction between water and air.

There must be movement on the surface of the water so that the air and water are in contact, this will bring oxygen. You therefore need a filter that sets the water in motion on the surface of the aquarium, or an air pump that will increase the oxygen level of the water. There is also the solution of oxygenating plants to buy in a specialist store.

> ⭐ Discover our range of air pumps for aquariums ⭐ <

When fish aren't getting enough oxygen, they will try to compensate by moving closer to the surface. You might also see a similar phenomenon when fish tend to stay close to the bubbles in your rock features. Unless it's a surface fish, there's no reason for it to open its mouth to breathe outside of the water.

If this is the case, it means that there is clearly a lack of oxygen that can be explained by injuries, parasites or even certain diseases such as flukes. But if the phenomenon remains global, that is to say if you have a group of fish carrying out the same modus operandi, then it is a safe bet that the conditions of their habitat are not optimal.

Pay attention to water quality

To fix this problem, you should start by performing a nitrite test , as well as a pH test of the water. You should investigate the possibility that you have a quality problem with an incorrect temperature, an incorrect pH level, too much ammonia, nitrates or nitrites.

> ⭐ Find here the material to analyze the water of an aquarium ⭐ <

Next, continue your investigations to understand why your aquarium is lacking oxygen. Your goal will be to improve the aquatic environment. If you ever have cloudy or polluted water, it could mean that you have added far too much food.

Also check that you do not have dead fish in your aquarium and if so, consider removing them. The same goes for rotting plants. These are sources of bacteria that will harm the quality of life of your fish. In any case, do not forget to replace the water in your aquarium to obtain a healthy balance.

Consider the possibility of overcrowding

When you have an aquarium with too many fish, you have natural pollution that sets in, resulting in low oxygen levels. In addition, bacteria can also grow more easily, but they will be sources of disease.

To avoid this phenomenon, it is important to respect the basic rule, that is, 4 l per adult fish of a size of 3 cm. This is a general characteristic, because again there are disparities between species that tend to pollute or consume more oxygen.

This is a rough guideline for determining the size of the aquarium and the number of fish. But to refine this result, do not hesitate to do additional research. At the same time, also invest in oxygenating plant species and an aquarium bubbler .

A ventilation problem

It is important to have moving water because it allows for better water quality due to the movement of surface water with deeper water. As a result, fish benefit from a better supply of dissolved oxygen.

To achieve this, it is impossible to ignore quality filters that allow the elimination of waste and also excess food. But you must check the filters regularly, because they may have certain defects or they must be replaced.

To bring a greater amount of oxygen into your aquarium, consider using bubble decorations such as an air stone.

Not only will you enjoy the many benefits of these elements, but you will add an extra decorative touch.

A water temperature that is not suitable for your fish

Water temperature also has an influence on oxygen concentration. Cold water contains more oxygen than warm water, so be careful in hot weather.

If you notice that the temperature of the aquarium tends to increase, you should cool it down and if necessary move it if you have direct sunlight. If the temperature is too high for a long time, your fish may not like it because of a drop in dissolved oxygen.

Feeding aquarium fish

• Conditioning : Fish can be conditioned to associate the water surface with food. If you always feed them by throwing food on the surface, they can get used to congregating there while waiting for food.
• Pavlovian Reaction : Much like the dogs in Pavlov's experiments, fish can develop a conditioned response. When they see a person approaching the tank or notice other cues associated with feeding time, they may congregate at the surface in anticipation.

Food Considerations

• Food Type : Some foods float on the surface, which can encourage fish to eat at the surface. On the other hand, foods that sink quickly will encourage them to forage in the lower layers of the tank.
• Frequency and Amount : Overfeeding can cause fish to stay at the surface, especially if they expect to be fed often. It is important to follow a regular feeding schedule and not overfeed your fish.

Of course, I can elaborate further on the point about feeding and its influence on the behavior of fish that stay on the surface of the aquarium.

Feeding and Behavior of Fish at the Surface

Waiting for Food

• Conditioning : Fish can be conditioned to associate the water surface with food. If you always feed them by throwing food on the surface, they can get used to congregating there while waiting for food.
• Pavlovian Reaction : Much like the dogs in Pavlov's experiments, fish can develop a conditioned response. When they see a person approaching the tank or notice other cues associated with feeding time, they may congregate at the surface in anticipation.

Food Considerations

• Food Type : Some foods float on the surface, which can encourage fish to eat at the surface. On the other hand, foods that sink quickly will encourage them to forage in the lower layers of the tank.
• Frequency and Amount : Overfeeding can cause fish to stay at the surface, especially if they expect to be fed often. It is important to follow a regular feeding schedule and not overfeed your fish.

Health Effects

• Buoyancy Problems : Improper feeding can cause buoyancy problems in some fish. For example, feeding too much air (such as certain types of flakes or pellets that float on the surface) can cause swim bladder problems.
• Water Quality : Overfeeding can also degrade water quality, increasing ammonia and nitrate levels, which can stress fish and cause them to seek oxygen at the surface.

To conclude

When fish stay on the surface of the aquarium, it can be a sign of several potential problems, some of which can be dangerous to the health of your fish. Here are the most common reasons:

1. Lack of Oxygen : This is the most common cause. If the aquarium water is not sufficiently oxygenated, the fish will rise to the surface to access more oxygen. This can be due to inadequate filtration, overcrowding, or water temperature that is too high (warm water retains less oxygen).

2. Poor Water Quality : High levels of nitrates, ammonia or toxic chemicals in the water can stress fish, causing them to seek fresh air at the surface. Regular maintenance and water quality testing are essential.

3. Diseases : Certain health problems, such as respiratory infections or swim bladder disease, can cause fish to remain at the surface.

4. Stress : Stress due to changes in the aquarium environment, such as new fish, bright lighting, or loud noises, can also cause this behavior.

5. Feeding : Sometimes fish will come to the surface waiting to be fed, especially if they have been conditioned to receive food in this manner.

Is it dangerous?

Yes, it can be dangerous. If fish are constantly staying at the surface, it usually indicates a problem in the aquarium environment that needs to be addressed quickly to ensure their health and well-being. Here's what you can do:

• Check Water Quality : Use a test kit to check levels of ammonia, nitrites, nitrates and pH.
• Improve Oxygenation : Make sure your filtration system is working properly and consider adding an air pump or air diffuser to increase oxygenation.
• Check the Temperature : Check that the water temperature is appropriate for the species of fish you have.
• Reduce Stress : Minimize stressors in the aquarium environment.
• Consult a Specialist : If the problem persists, it may be helpful to consult a fish veterinarian or an experienced aquarist.

It is important to act quickly, as remaining at the surface for an extended period of time can be harmful to fish and indicate environmental problems that need to be addressed to ensure the health of your aquarium's ecosystem.