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Betta Fish Temperature Shock: Symptoms & Treatment

Brooke Billingsley

By Brooke Billingsley

half moon betta fish surfacing

Like most fish, Bettas are sensitive to rapid changes in temperature. This is typically not something that’s a problem in a well-maintained home aquarium, but temperature shock is a big risk when performing water changes or when you bring your Betta home for the first time. Temperature shock can be deadly for Betta fish, especially if they rapidly enter water that is much cooler than what is safe or comfortable for them. When it comes to temperature shock in Betta fish, here are the things you need to know.

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What is Temperature Shock?

Temperature shock is a physiological reaction in the body that occurs when temperatures rapidly change. Imagine the feeling you get when you step from a well-airconditioned house into a humid summer day. You’re immediately uncomfortable and you may even feel like the air you’re breathing quickly became more difficult to breathe in. This is a similar physiological reaction to temperature shock in Betta fish. However, stepping from a cool to a hot place is uncomfortable for us, while temperature shock can be deadly for Bettas.

Temperature shock causes a rapid change in your Betta’s internal body temperature, leading to a shocked state where they may have difficulty moving oxygen and swimming. Rapid swings in temperature can also lead to difficulty with proper metabolic activity in the body, decreasing the efficiency or overall functionality of the internal organs.

betta fish in aquarium
Image Credit; ivabalk, Pixabay

How to Prevent Temperature Shock

When introducing a Betta fish to a new environment, the easiest way to prevent temperature shock is to float them in a bag in the tank they will be going into. This will allow the temperature in the bag to slowly match the temperature of the tank. This takes around 20–30 minutes typically. After the temperature has adjusted, you can begin slowly adding tank water into the bag to allow your Betta to adjust fully to the temperature and the parameters of the water.

Take Precautions Ahead of Time

If you are performing water changes, then you should take precautions to prevent temperature shock. If your Betta fish’s tank stays at 75˚F, but you replace the tank water with cold water from the tap, then you may change the overall tank temperature too rapidly for your Betta fish, causing them to go into shock. This can be avoided by preparing water ahead of time and allowing it to reach room temperature or warmer and then adding it to the tank very slowly over at least a few minutes to allow for safe acclimation.

man changing water in aquarium
Image Credit: hedgehog94, Shutterstock

Invest in a Reliable Tank Heater

The easiest way to prevent temperature shock for your Betta fish is to invest in a reliable tank heater. Maintaining the temperature in a range of 78–80˚F is ideal, but Bettas can thrive in water between 72–82˚F. Even at the lowest part of this temperature range, room temperature water will almost certainly be too cold for your Betta fish. A tank heater that maintains the tank temperature in a range of 2–5˚or less is ideal. Avoid keeping your Betta’s tank in a location where it will have air from your air conditioner or heater blowing directly on it.

What are the Symptoms of Temperature Shock in Betta Fish?

The most common symptom of temperature shock in Bettas is rapid gill movement or gasping for air. They also may rapidly become lethargic or stop moving altogether, except for gill movement. If your Betta has suddenly been exposed to water that is too cool, then you’re likely to see lethargy and loss of color. Warm water is more likely to lead to respiratory symptoms than cool water. You may also see abnormal swimming patterns and your fish spending a lot of time at the surface gulping air. Keep in mind that breathing air is normal for Bettas, but if your Betta is spending long periods of time at the top gulping air, then there may be a problem.

betta fish in aquarium
Image Credit: yin8003211, Pixabay

What is the Treatment for Temperature Shock?

The best treatment for temperature shock is to adjust the temperature to a safe range. Do this somewhat slowly. If your Betta has just been shocked with cold water, so you dump hot water into the tank in an attempt to balance the temperature out, then you will likely make things worse for your Betta fish. Aim to change the temperature around 2–3˚ every hour until you reach a safe temperature. Don’t expect your Betta to suddenly feel better when the temperature is corrected, though. It may take time to recover.

Water temperature can slowly be raised with a tank heater. This is the safest and most reliable way to raise the water temperature without risking further shock or burns. To lower the water temperature, you can float a frozen water bottle or small bags of ice in the tank. You can also slowly add cool water to the tank, but still with the intention of not altering the temperature more than 3˚ every hour. It’s important to add cool water, not cold water. Ice water or water from your refrigerator may drop the temperature too quickly.

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Final Thoughts

Unfortunately, there aren’t really ways to treat temperature shock in Betta fish except to correct the temperature. It’s important to take precautions to prevent temperature shock in the first place. Otherwise, you’re risking your Betta’s life, even if you immediately begin working toward fixing the water temperature. A reliable tank thermometer and heater are your best tools to prevent temperature shock from occurring.


Featured Image Credit: at.rma, Shutterstock

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