can a fish have a seizure?

Can a fish have a seizure? Debunking The Myth

Fish keepers often ask the question, “do fish have seizures?” This can be a difficult question for fish keepers to answer because, sometimes, it’s not clear whether the fish are having seizures or if they’re gasping. A seizure in an aquarium is typically characterized by intense splashing and thrashing of the body.

We can answer this with a resounding yes. Fish can sometimes experience seizure-like activity when they are sick or in shock, but let’s discuss why fish do not always have these episodes and what you can do to help your pet recover.

Fish Seizure

Yes, it’s true! Fish can have seizures, but they’re not as common and are more likely to happen when stressed or in poor health than with other animals like humans.

True Seizure VS Fish Seizure

One needs to understand is that an actual seizure involves uncontrolled muscle contractions and an abnormal electrical discharge of the brain cells. For a fish to have a seizure, they would also need to be vertebrates and have an evolved brain. Fish can look like they are having seizures, but it’s more likely that their scales or fins just maybe moving erratically because of water currents.

In addition, the most common cause for sudden mortality in aquarium fish is usually from other factors that we will discuss in this article.

  • Poor nutrition
  • Injuries from fighting with other fish in the tank or another outside source
  • Very high nitrate levels in water can affect a lot of things like organ function, immunity, and even behavior. This is why it’s essential to keep an eye on your aquarium’s nitrates at all times.
  • Lack of oxygen can be another cause, and this is why you should always use an air pump in your tank to help provide a good amount of oxygen.

So, unfortunately, fish can’t have seizures since they don’t have a brain developed enough for that! However, plenty of other factors can lead to sudden death in aquariums, so make sure to keep an eye out for any of these.

Can a Fish Have a Seizure? Questions for the Expert

A fish’s seizure might look like the fish is gasping at times, but they’re gulping for air. Sometimes these episodes will last only a few seconds before it stops or goes away on its own while other times you may need to watch them closely until they come out of this episode. Trying to figure out what’s happening can be difficult, but if you do notice an episode of intense gulping and thrashing, then it’s likely that your fish is having an ‘aquarium seizure.’

Symptoms that your fish is having a seizure

But first, you need to identify if what you’re observing is a seizure or not. When the fish is having a seizure, it can be easy to tell because they will start thrashing around.

It might seem complicated to determine what caused the episode, but these are some of the symptoms:

  • A loss in appetite and interest
  • The fish’s skin becomes pale or bluish
  • Fish slows down its movements and its breathing
  • Swimming becomes erratic, and fin movements are uncoordinated
  • The fish’s head might droop down, or it can swim upside down as if going in circles.
  • Symptoms of a seizure vary from one fish to another, but the symptoms mentioned above should help you identify the cause for your pet. Once you know what is causing it, you must treat the cause.
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What is the Difference Between Seizure and Anxiety in aquarium fish?

What are the Most Common Causes of Fish Seizure?

The most common causes of a fish seizure are electrolyte imbalance, water quality issues, and oxygen depletion. So here, we will discuss each cause in detail.

Bright light or outside noises

The most common reason that a fish will have one is when your fish is exposed to bright light or outside noises. For example, if you place your aquarium on top of the television while watching it and turn up the volume without realizing what is happening – that can be enough to trigger seizures in some species of fish. 

So it’s important to keep your aquarium dark. If you’ve disturbed the fish and they seem upset or stressed out, try giving them a few minutes before approaching again. It is not uncommon for fish to avoid bright light so they can feel safe and comfortable. Therefore, to provide them with an instant hideout place, you can set up a planted aquarium.

Fish have an anatomical lateral line to detect changes in water pressure. The lateral line is a series of canals that run along the length of their body and house sensory hair cells to sense vibrations, currents, depth, and other physical stimuli.

Fish suffocation in the water

Fish can have seizures, but it is rare for a fish to do so. Usually, in aquarium settings with healthy water parameters, seizures are very slim or unlikely. The most common cause of seizure or thrashing in aquariums has been attributed to low oxygen levels caused by inadequate aeration and gaseous buildup, and high levels of nitrates.

You mustn’t use a filter with carbon because it removes oxygen from the water, which can cause fish to suffocate.

As well as this, it’s important for you not to overcrowd your aquarium because excessive amounts of ammonia can harm or kill tank inhabitants as well as decrease the oxygen level.

These are the most common causes for seizure in aquariums and can be avoided by maintaining a healthy environment with adequate aeration, proper nitrogen cycle maintenance, low ammonia & nitrite levels, plus water changes to eliminate the buildup of excess waste products in the tank.

Temperature Shock and Fish Seizure

Temperature shock can cause fish to have a seizure as fish can also feel the temperature change on different parts of their bodies, allowing them to react when they come into contact with warmer water and surroundings. The water temperature in an aquarium should not change abruptly, but sudden changes can happen due to a power outage or problems with the heater/pump system. When this happens, all other parameters such as pH and oxygen levels need to be closely monitored because these factors can also get affected.

Fish can have seizures due to temperature shock. This is because sudden changes in water parameters (such as pH and oxygen levels) can result from a power outage or problems with the heater/pump system.

It is recommended that all other aquarium parameters be closely monitored when this happens, such as fish behavior and the general appearance of the fish. Suppose an aquarium owner observes changes in behavior, appearance, or other symptoms. In that case, it is recommended that the water be tested and treated with medications as necessary to stabilize conditions before adding new fish to the aquarium.

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Viral, bacterial, and fungal infections and Fish Seizure

Fish can experience seizures for a variety of reasons, including trauma or viral and fungal infections. The most likely cause is an infectious disease called ichthyophthirius multifiliis (Ich), but it can also be due to bacterial infection from Aeromonas spp., Pseudomonas, or Vibrio spp.

Falling into the aquarium can also cause seizures in fish, and bacterial infection from ichthyophthirius multifiliis (Ich) is a leading culprit. The Ich parasite attaches to some fish’s gills or skin, causing irritation and eventual death as it spreads throughout their bodies. Treatment for this type of parasite is complex and can include medications like copper sulfate, formalin, malachite green.

How to calm your fish down from a seizure?

When fish experience a seizure, they can get very frantic and start to swim in circles.

  1. Clear their path

    The first thing you should do is remove any plants or other items that might be getting stuck on the aquarium floor, which could cause them difficulty when moving about.

  2. Spray some vinegar

    Next, try spraying the water with something like vinegar, as this will help dissolve some of the substances on the aquarium floor that can cause a seizure.

  3. Hydrogen peroxide and Decore

    You might need to use something like hydrogen peroxide or try removing any decorations in your tank, which could be causing their stress (e.g., if they’re stuck on an object).

  4. Salt Bath

    If those remedies don’t help calm them down and stop the seizure from continuing, you can also try giving them a salt bath by adding two cups of aquarium water to the fish’s tank.

  5. Talk to an Expert

    If this doesn’t work, then you should take your fish to an expert for advice on what can be done next.

Which Aquarium Fish is prone to this episode

Many aquarium fish are prone to these episodes, especially when they’re not feeling well or in distress. At the exact moment, you might not know what caused it to make you unable to help, so it is not much you can do. However, you must understand why the episode happened and then treat the cause and the fish accordingly.

So as we have mentioned before, not all fish experience seizure-like episodes. However, the many aquarium fish prone to these episodes can include Angelfish, Betta Bala Sharks, Clown Loaches, Goldfish, and Koi.

  • Angelfish: can sometimes experience seizure-like episodes due to poor water quality or when they’re stressed.
  • Clown Loach: could be experiencing sudden death from suffocation and is more prone in their juvenile stage of life since the gills are still developing.
  • Goldfish: can also have a seizure caused by poor water quality.
  • Koi: can be more prone to a seizure if they are too cold or not given enough room for swimming and exercising in the aquarium.
  • Betta: They can sometimes experience a seizure-like episode if they’re not given enough oxygen in the aquarium.

What is causing the Sudden Death of my Fish?

If the aquarium fish died suddenly, then there is a good chance that he/she had an episode of seizure, but there might be other reasons that your fish have sudden death.

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Some common causes can be :

  • Low water temperature can be one of the reasons. It is vital to maintain a stable aquarium environment for your fish.
  • Changes in tank parameters such as pH, ammonia, nitrite levels, or even salt level can also lead to sudden death among your aquarium inhabitants. These changes need not occur all at once but rather may take place stepwise over a period of time.
  • Stress can cause sudden death in your aquarium fish, and this is usually caused by living conditions that are not ideal for them, mishandling, or even rough handling from novice aquarists who have no idea how to handle their new pet.
  • A bacterial infection may also be the culprit if there were symptoms of such infection beforehand, such as red streaks on the body, ragged fins, and even cloudy eyes.
  • Parasites can also be responsible for sudden death in fish if visible signs of parasites like white larva or cysts come out from their gills or wounds.
  • A lack of appropriate tank mates may also lead to sudden death if there are no fishes to play with and keep your fish entertained.
  • Stroke is also a cause of sudden death in aquarium fish, but this can be prevented by being sure that the water has been filtered properly as well as changing it regularly, ensuring the tank mates are compatible with each other and giving appropriate shelter when needed like having plants or hiding places in the tank.
  • Fish can also have seizures, and this can be caused by lack of oxygen, low temperatures, or chemical imbalance in their body, like with a toxin from plants they ate.

Frequently Asked Questions:

Can Fish Have Seizures?

No, fish cannot have a seizure.
A true seizure occurs in the brain and causes uncontrolled movements of body parts, including muscles. This can be accompanied by loss of consciousness, confusion, or, much less commonly – changes in mood such as depression.

How much time does it take a fish to die after an episode?

Most aquarium fish will die within 24 to 48 hours once they’ve had a seizure if no treatment is given, but it’s good practice to isolate the fish in a separate container to be sure.

When to contact the Pet Shop? 

If you suspect that your aquarium has been poisoned, or if it’s polluted with chemicals from an accident, then contact the pet store for advice because they can determine what type of poison is involved and recommend treatment for different types of poisoning.


If you are concerned about your fish or know someone who is, it’s essential to understand the different causes of seizures in fish. We hope this article has helped answer some questions and provided potential solutions for these issues. If there’s a specific question we haven’t addressed here, please feel free to submit your queries below. We are here to help you find the answer that you need. If your fish has had a seizure, we want to know about it, so do share your stories. 

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