Top 9 Reasons For Fish Swimming In One Spot And How To De-Stress A Fish

If you have just introduced a new fish to your tank, you may observe that they stay in one spot without moving. While some are naturally reclusive or shy, which makes them reluctant to move around and explore, some can exhibit strange behaviors due to external factors.

If you’re a beginning aquarist and share the same concern about fish swimming in one spot, this article will clear your path. Besides, we also share some valuable tips to reduce stress for your fish. So, keep reading!

fish swimming in one spot

9 Reasons Why My Fish Stays In One Spot


The possible reason your fish may stay in one spot is that they just prefer one spot in the tank over another. Maybe because the area has a thicker algae growth that they can feed on or a favorite hiding place they enjoy.

While this doesn’t mean a significant issue, you may want to promote full-tank usage with various compatible fish types and sizes for a lively fish tank display.

Water flow

Depending on the type of pump and water filter system of the tank, the water currents may flow to facilitate fish to steer in one specific place. Hence, ensure the pump you’re using is suitable for the tank, so it does not unintentionally confine the fish to just one side of the tank.

Water temperature

While most aquarium heaters do well at keeping water temperature stable, you may find your fish staying on one side of the tank where they feel comfortable. This is because your water heater might be of low capacity, causing inconstant temperature throughout the tank.

In this case, consider purchasing two submersible thermometers and putting them on both sides of the tank. Then, constantly measure the water temperature and make adjustments for the heating system if needed to keep the water temperature within the advisable range.

Hiding places

If you set up plants or aquarium decorations such as rocks and wood on one side of a tank, you may notice several fish hanging out there because hiding is an instinct for fish.

But try setting up the plants and decorations throughout the tank instead of in one place to provide a wide range of hiding places for your fish. Also, it makes them active to come out and explore more.

Tank mates

In a fish community, larger fish is likely to attack or even kill smaller fish. Therefore, to avoid being attacked, a particular group of small fish tends to occupy a corner of the tank by staying in one spot, especially when the tank is a confined area, so they do not have any choices besides finding a place to hide.

To ensure your fish live comfortably with other species, it’s recommended to research fish compatibility before deciding on new fish pairs for your aquarium.

fish's tankmates


Another reason for fish staying still is that they feel stressed or tired. Stress can be caused by several factors, such as a shift in water volume or heat or the overpopulation of predatory or aggressive fish. In this case, try to adjust their environment and provide them with some hiding places where they can rest and feel safe.


Illness such as fin rot is another factor that makes it challenging for fish to move around because they are vulnerable and do not have any energy. Instead, they are likely to stay in one place and avoid eating food and interacting with other tank mates.

When you find your fish has abnormal behavior, it might indicate that he is sick. Hence, it’s vital to transfer him to a quarantine tank and provide him with the appropriate treatment as soon as possible.


Just like humans, fish need to sleep. They tend to sleep with their eyes wide open since they do not have eyelids. When they sleep, they float in place or stay still in a secure spot, often at the bottom or near the water’s surface. But they also need to keep moving a little so water can constantly move past their gills, maintaining a proper oxygen level in their bodies and allowing them to breathe while asleep.

do fish sleep?

Fish tank environment

When the fish is first introduced to the tank, he may find a spot to stay. It is because he needs some time to adapt to water quality, temperature, and tank mates. Hence, do not try to tap on the tank glass to make him move. Instead, be patient and allow him to explore and adjust to a new environment.

Why Are My Fish Swimming In One Corner?

Fish can show many behaviors that tell us how they feel, and swimming in one corner is one of them. The primary reason for this could be the water is inefficient, unsafe, or bacteria have spread into the tank.

Other reasons might include:

  • They swim in a warmer/colder spot of their preference.
  • They are sleeping.
  • They hide from larger fish.
  • They get sick and do not have the energy to move around.
  • They are stressed.

But some fish enjoy swimming at one side since they are comfortable with the temperature and tank mates. In this case, do not try to disrupt and move them around.

In case you notice they are isolated due to aggressive tank mates or vulnerable because of diseases, it’s time to separate them from those hostile fish or quarantine them if they catch a disease.

How Do You De-stress A Fish?

If you determine that your fish is dealing with stress, it’s time to take action.

Depending on the situation, you can try:

  • Use a water test kit to make sure the tank environment is at optimal pH, nitrate, and ammonia levels for your fish. Adjust if necessary.
  • Check the water temperature to ensure it is stable.
  • Provide an effective filtration system that prevents debris and bacteria.
  • If you notice bullying behavior from larger fish, remove them and place them in a separate tank.

Wrapping Up

So, you’ve probably found out some potential reasons for your fish swimming in one spot. While some enjoy one place over another due to suitable conditions, some choose to stay still because of aggressive tank mates or an uncomfortable environment. Hence, it is always advisable to build appropriate conditions in the tank to prevent stress for the fish to live happily and healthily with their tank mates