Can Fish Feel Anxiety? Your Pet Fish Could be Anxious



  • Fish can get anxious due to changes in their environmental conditions.
  • Some fish like zebrafish can be anxious in an open tank. Many fish also prefer dark aquariums over light. Otherwise, get anxious.
  • Fish can be traumatized or suicidal due to anxiety.
  • By turning lights off, providing good food, and turning music on, a clean and playful environment can help to calm an anxious fish.

All the fish lovers or those who have pet fish think once in life, “Can Fish Feel Anxiety”? And after this thought, most people browse to find an answer.

Shortly, the answer to your thought is yes. But if you want complete information on the anxiety of fish and ways to overcome it, then read this blog post further.

Can Fish Feel Anxiety? – Experts Say Yes

Experts are clear that Fish can feel anxiety. Fish behavior, neurodevelopment, endocrine system, and brain organization closely relates to other vertebrates, including human.

Various tests are performed on fish for the behavioral study of human anxiety. Zebrafish, guppies and cleaner fishes have been used as behavioral models to analyze anxiety test success. These Fish are used for anxiety analysis. It means that the Fish has feelings of anxiety.

In Zebrafish, feelings of fear and anxiety have been discovered and widely studied. Two ways have been used to study anxiety in Fish. One is an Open tank test, and the other is a light or dark one.

Through behavioral study, it has been discovered that bottom-dwelling, leaping, thrashing, stereotypy and escape are the specific signs of anxiety in Fish. These signs have been shown through an open tank test.

According to studies, Zebrafish feel anxiety - Can fish feel anxiety?

In Zebrafish, bottom-dwelling and thigmotaxis are the most common indicator of anxiety. Several researches have shown that Zebrafish spend 70-80% of their time in the bottom of the tank when kept in to open tank for some time. This shows the anxiety of Zebrafish.

Why do Fishes have Feelings of Anxiety? 2 Common Reasons

There are two main conditions in which Fish feels anxiety. According to many researches, anxiety prevails in Fish if they are kept in an open tank or light is turned off or on.

1. Do Fish Feel Anxious In Open Tank

Yes, Fish, especially Zebrafish, don’t feel comfortable in an open tank. Anxious behavior has been discovered in Zebrafish when they are kept in an open tank. Zebrafish dwell on the bottom when anxious. It tries to hide from the exposed environment. In some cases, thrashing behavior is also observed.

According to scientific research, Fish feels anxiety and their signs of anxiety are mentioned.

2. Does Turning the Light On/Off Stress Fish?

Scototaxis (Dark or Light) models have been studied in some fishes. Most commonly, this observation has been performed on Zebrafish. Zebrafish or goldfish were kept in the white compartment. During the stay in the white chamber, anxiety behavior was observed in Fish.

There was another dark compartment in the aquarium. When the separation was removed after 5 min between chambers, Zebrafish moved to the dark one. It proves that Zebrafish prefers dark container over light.

Fish can feel anxiety due to light or too dark environment.

Due to environmental enrichment, anxiety decreases in Zebrafish when it moves to the dark compartment. Similarly, thigmotaxis (the ability of Fish to stay near the walls of an aquarium) is an indication of anxious behavior in Fish.

Therefore, we must turn the lights off for Fish, especially Zebra or Goldfish.

Can Fish Be Suicidal From Anxiety? Yes, they Can

You know Fish can commit suicide too. Due to anxiety, fish can die. If your aquarium has a bright light, it could lead to death.

For instance, betta feels stress and anxiety if there is too much light in the tank. Due to stress, betta may show abnormal behavior and tries to escape from the aquarium. When it doesn’t find a way to escape, it ultimately commits suicide.

Similarly, Zebrafish and Goldfish cannot live in the light and prefer a dark environment.

The fish tries to escape from an unfavorable environment and overreacts. If escape is not possible, fish adapt to the new conditions.

In some cases, fish don’t adjust to the new environment and remains anxious. Therefore, its immune system gets weakened. It strives to adapt to the new environment but fails. Ultimately, it commits suicide.

How Long Does Fish Anxiety Last?

The time in which anxiety diminishes in Fish depends on environmental enrichment. If a fish becomes anxious in light, then it depends on the owner how much time it takes to create darkness in the aquarium. Your care and action will determine how long the fish stays anxious.

So, act immediately whenever you observe anxiety in Fish.

How do You Calm an Anxious Fish? 5 Ways

When your Fish get anxious, please don’t ignore them. Must take immediate action. For this purpose, the following ways will help you to calm an anxious fish.

  1. Turn Lights Off – If your Fish hates lights, make the aquarium dark. Turn the lights off and create a darker environment for them.
  2. Don’t Keep in Open Tank– Fish may feel anxious due to the open tank. Therefore, close the tank to calm your fish.
  3. Change the Food – Fish may get bored or anxious due to the same food. So, give them new favorite food.
  4. Turn Music On – Some fish feel calm and relaxed when they listen to music. Don’t play loud music; use classical music. If it works, then try it for your Fish.
  5. Provide a Clean, Playful Environment – Due to a dirty environment or water, anxiety may arise in Fish. Keep the aquarium environment clean and healthy. Add some rocks and plants. In this way, anxiety in fish could be lessened.

Do Fish Get Traumatized? Avoid Stressful Situation

Definitely, Fish get traumatized in traumatic or stressful conditions. These conditions can lead to the death of fish or abnormal behavior. The effect of the traumatic situation may last longer in some cases.

When Fish feel fear or danger, the adrenaline (fight/flight) hormone level rises. These hormones boost the energy of Fish to move away from danger. The natural level of salts and water gets disturbed due to these hormones.

Similarly, in fear, cortisol level also increases. These hormones affect the immune system and weaken it. Therefore, fish get traumatized by stress or anxiety.

After stress or fear stimuli, Fish can regain their abilities, but it may take approximately an hour to some days.

Do Fish Relieve Anxiety? Social Support

According to scientists, fish can relieve anxiety and improve mood. They give social support. Fish shows affection and friendly behavior when you take care of them.

Fish relieve stress of an owner - Fish relieves anxiety

These tiny creature helps to reduce loneliness and stress. When we see Fish, we can forget our worries. Therefore, it is recommended to get some fish as it relieves anxiety.


Scientific evidence shows that Fish can feel anxiety. Therefore, you should care about the feelings of your beautiful, friendly Fish.

Do your Fish ever felt anxious? How does it react when it feels anxious? What ways work for your anxious fish? Let us know in the comments.


  1. Soares, M. C., Cardoso, S. C., Carvalho, T. D. S., & Maximino, C. (2018). Using model fish to study the biological mechanisms of cooperative behaviour: A future for translational research concerning social anxiety disorders?. Progress in Neuro-Psychopharmacology and Biological Psychiatry, 82, 205-215.
  2. Gerlai, R., Fernandes, Y., & Pereira, T. (2009). Zebrafish (Danio rerio) responds to the animated image of a predator: Towards the development of an automated aversive task. Behavioural Brain Research, 201(2), 318-324.
  3. Blaser, R., Chadwick, L., & McGinnis, G. (2010). Behavioral measures of anxiety in zebrafish (Danio rerio). Behavioural Brain Research, 208(1), 56-62.
  4. Hope, B. V., Hamilton, T. J., & Hurd, P. L. (2019). Submerged plus maze: A novel test for studying anxiety-like behaviour in fish. Behavioural Brain Research, 362, 332-337.
  5. Maximino, C., Marques de Brito, T., Dias, C. A. G. D. M., Gouveia, A., & Morato, S. (2010). Scototaxis as anxiety-like behavior in fish. Nature protocols, 5(2), 209-216.
  6. Epinephrine (Adrenaline) by Cleveland Clinic

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