What Causes Guppies to Swim at the Top of the Tank?

A tank filled with guppies is a wonderful display! No wonder it’s a top choice for most pet fish owners and enthusiasts.

However, some fish species can behave out of the norm, leading to curiosity and, in some cases, distress to the owners. One such behavior is when guppies start swimming at the top of the tank. If you’ve noticed your guppies doing the same and don’t know the answer, you’ve landed on the right page.

What causes my guppies to swim at the top of the tank? This is an indicator of the shortage of oxygen or the lack of it completely. Another possibility would be that the tank could be deep, and the guppy wants to rest its gills and get more oxygen by floating.

In this article, we will discover why a guppy fish might swim close to the surface of water.

Guppies’ Swimming Behaviors

It is always a good idea to get a group of six or more guppies together and place them in the same tank. They are sociable creatures, and they get along easily.

It is recommended to place them in the same tank as some other fish types, like neon tetras, catfish, and platies, for example. Peaceful little fish would make great companions for guppies.

Guppies are very peaceful creatures. They do nip at other fish’s fins as many fish do, but this behavior is not a means of attack or animosity. It is just an instinct.

Now when we talk about the guppies’ swimming behaviors, it is necessary to detect their manners of swimming and patterns. Guppies swim actively all around the tank. They will be scattered everywhere and not in a specific fixed manner.

Unlike the neon tetras who swim in schools, guppies swim in all directions and independently. Their random swimming pattern makes them look interesting and playful. Therefore, it is always going to be easy to spot if there’s a problem with how a guppy is swimming.

If you notice a difference in the swimming pattern of your guppies, immediately check the water and the lighting. When guppies are hungry, you will notice that they are swimming at the top of the tank, waiting for their food.

Guppies are greedy eaters. Even though their bellies could be filled with so much food, you would still find them hungry and begging to be fed again. Yet, you should never feed them more than twice daily. Plus, their food should be in flakes and small pieces.

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Guppies are very similar to neon tetras, which is why it’s convenient to keep these two species together in the same tank. They share similar tank requirements, making it easier to maintain their habitat. Plus, having both in one tank results in a vibrant, colorful, and cheerful aquatic display that’s not only visually stunning but also an excellent choice for beginners looking to create an eye-catching and manageable aquarium.

Physical Attributes to Watch Out For

Guppies’ Fins

Guppies’ fins are very interesting to pay attention to. Guppies have a special capability to spread out their fin rays. This is a sign of healthy guppies. Do not be confused or concerned.

However, you may worry if you get guppies with fins pressed against their bodies. This could indicate illness or stress. If you notice that, pay attention to other signs that could be indicating a serious health problem.

Look out for white spots, dots, or patches on the fins, holes, or ribs. These are tell-tale signs that the guppy is not in a healthy state and needs to be checked by a vet.

When selecting guppies at a pet store, avoid choosing individuals with ragged fins, as this is often a sign of fin rot and poor health. The condition of a guppy’s fins can be a clear indicator of its overall health, so it’s essential to pay close attention to this aspect when making your selection. Observing their fins can provide valuable insights into their well-being and help you make an informed choice.


Indeed, assessing more than just the fins is crucial when selecting guppies. Pay attention to the guppy’s head as well. Clear and non-cloudy eyes are a positive sign, while guppies with protruding eyes may be suffering from a condition known as “Popeye,” often caused by infections behind the eyeball.

Additionally, observe the gills; rapid breathing and abnormal gill movement can indicate serious health issues that may require veterinary attention. Lastly, inspect the mouth for any signs of ulcers. Ensuring the health of your guppies is paramount, as illnesses can easily spread in a tank with various fish species.


Now it is also better to double check for your guppy’s good health. When it comes to the body, you have to watch closely and check if the belly is swollen or not.

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A swollen belly in guppies is typically a positive sign, as it often indicates pregnancy. Healthy guppies will have rounded bellies when they are expecting. However, a sunken belly in guppies is cause for concern, as it can signify an infection.

Any spots or patches on their bodies may be indicative of bacterial or parasitic infections, which should be addressed promptly to maintain the overall health of the fish.

Guppies Swimming at the Top of the Tank

If you notice your guppies constantly hovering near the top of the tank, it could be a sign of oxygen deficiency, causing them to struggle for breath. To remedy this, it’s essential to invest in an oxygenating pump to maintain a healthy oxygen level in the water.

Guppies inhaling air from the water’s surface is not ideal for their well-being. Creating water movement can also help distribute oxygen evenly, ensuring your guppies have a comfortable and oxygen-rich environment to thrive in.

Apart from oxygen depletion, other reasons why your guppies may be swimming at the top of the tank include:

  • Overcrowding can lead to reduced oxygen levels due to the increased fish waste and respiration. Guppies may swim at the top to find more oxygen-rich areas.
  • Poor water quality, including high ammonia or nitrite levels, can stress guppies and drive them to the surface. In such cases, testing and improving water conditions are crucial.
  • High water temperatures can lower the oxygen-carrying capacity of the water, causing guppies to seek the surface for more oxygen.
  • Guppies may exhibit abnormal swimming behavior when they are unwell, possibly due to diseases or parasitic infections. Keep an eye out for other symptoms and quarantine affected fish if necessary.
  • Pregnant female guppies might appear near the surface, especially when close to giving birth. This behavior is typical as they prepare to release their fry.

Frequently Asked Questions

Do guppies breathe air?

No, they do not. They need oxygenated water to breathe.

Do guppies need a filter? 

It is not necessary to keep a filter for the guppies because they do not produce much waste like the neon tetras. But filters would always help in purifying the water, so it would help improve the water conditions.

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Nadine Oraby

My name is Nadine; I am a passionate writer and a pet lover. People usually call me by the nickname “Joy” because they think that I am a positive and joyful person who is a child at heart. My love for animals triggered me to create this blog. Articles are written by vets, pet experts, and me. Thanks for visiting. Your friend, Nadine!

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