Skip to Content

Can I Add Warm Water To My Betta Fish Tank?

No, adding warm water to a betta fish tank is generally not a good idea. Bettas need to have their tank maintained at a constant temperature between 78 to 80 degrees Fahrenheit. 

Adding warm water to the tank may be a temporary fix, but the water will eventually cool, causing frequent swings in temperature that are not good for your betta. 

Constant fluctuations in temperature can cause bettas to experience stress and shock, ultimately leading to bettas becoming sick. Bettas must maintain constant warmth, and sudden dips in temperature or constant fluctuations will harm them. 

However, there are some ways to use warm water in your betta fish tank responsibly as a temporary measure. Read on to find out more!

Can warm water be used as a temporary solution?

Can warm water be used as a temporary solution

Closed hot water bottle

Warm water can be used as a temporary solution if used cautiously. If a power outage occurs and the temperature in your betta fish tank begins to dip, several options exist. 

In a pinch, grab a bottle that can withstand hot temperatures and fill it with hot water around 120 degrees Fahrenheit. 

Be careful handling the hot water and wear heatproof gloves to reduce the risk of injury. Seal the bottle and add it to your betta tank. 

As the bottle floats to the top of the tank, the water temperature will gradually increase. Keep a close eye on the temperature by using a thermometer; once the temperature reaches between 78 to 80 degrees, remove the bottle. 

Keep another hot water bottle available for when you need to place it in the tank again. This method will require constant vigilance to ensure the water does not get too hot. 

Also, ensure the bottle is hidden behind decorations and not easily assessable by your betta to lessen the risk of getting burnt.

Gradually adding warm water.

If there is no other option but to add warm water, the safe way to do it is to gradually switch out some water for warmer water. 

Keep a close eye on the temperature and gradually increase the temperature by one degree per hour until the desired temperature is reached. 

If a large amount of hot water is added to the tank quickly, the temperature will increase too quickly, and the rapid change can be fatal to your betta. 

Make sure that the warm water that is being added to the tank has been treated and closely matches the PH levels of your current betta tank. 

The warm water should not have a high concentration of salt or chlorine. Aim to keep the pH levels around 7.2 to 7.6. These steps will ensure a smoother transition for your betta fish tank when in a clutch. 

What are safer alternatives to warm water?

What are safer alternatives to warm water


The safest heating method to use in your betta fish tank is a heater. An adjustable heater will consistently maintain an ideal temperature for your betta. 

Interesting READ  How Big Will A Shark Grow In A Fish Tank?

Set the temperature to 78 to 80 degrees, and the heater will take care of the rest. This method is the most efficient and easy way to ensure the temperature stays regulated without much work on your part. 

The heater can be left on all day if it has a constant power supply. When the tank reaches the temperature set, it will automatically shut off and turn on again once the temperature starts to dip. 

This option means fewer things for a betta owner to worry about. 

Heating Pad

Another great alternative to warm water is to use a heat pad. Heating pads are typically placed under the fish tank and can keep your betta tank warm without any harm to your betta. 

It usually comes with a temperature controller that is easy to adjust and gradually increases the water temperature. Heating pads are not suitable for submersion but are water resistant. 

The added benefit to heat pads is since it is kept underneath the tank, bettas will not have the opportunity to play around them and get stuck between them as opposed to a standard heater. 

Since the heat pad is placed under the tank, there is more space for decorations, and it is less intrusive, making for a more visually appealing aquarium.

Heat Pack

Heat packs should only be used as a temporary option if there are no other safe alternatives and should only be used in conjunction with a thermometer. 

Heat packs specifically made for aquariums are usually used when transporting live fish and, depending on the brand, can give the tank steady, consistent heat for a few days. 

This is a great option to use during power outages or if something happens to your heater or heat pad. 

Since it only lasts for a few days at most, it is best to use it as a temporary measure while seeking more permanent solutions. 


A temporary option to use with your betta aquarium is insulation while placing the tank near a heater or window with direct sunlight. 

However, placing the tank in these areas, especially in direct sunlight, can cause algae to flourish. 

Excessive algae create too much waste in the water and produce too many bacteria and ammonia, which are harmful to betta fish. Only use this method as a last option and only temporarily.

Insulation that can be used is styrofoam, foil, foam board insulation, or even a blanket. 

While this method will increase the temperature in your betta tank, it should be closely monitored since there is no way to regulate the heat. The tank can become too hot too quickly. 

Use this method with a thermometer, and as soon as a temperature of 78-80 degrees is reached, remove the insulation. This method requires careful monitoring and work to ensure that the temperature does not fluctuate wildly. 

Essential tips on water temperature

Warm Water Temperature Tips

Whether you live in a warmer or colder climate, the temperature in your betta tank should always be monitored to maintain a constant temperature. 

Interesting READ  Can Ember Tetras Live With Betta Fish?

Here are some warm water temperature tips to help keep the temperature stable and your betta healthy and happy. 

Regular checks on equipment

Keep an eye on the thermostat to make sure the water does not dip or constantly fluctuate. If using a heater, do a regular maintenance check to make sure the heater is working properly. 

If the heater breaks and the thermostat no longer functions properly, the water can get too hot too quickly. 

Lighting systems produce heat too.

If using a lighting system, it could artificially increase the water temperature. Keep that in mind if the water temperature is too hot. 

Depending on the fish tank’s size, the lighting system could be sufficient to use. 

Natural or environmental conditions

Keep an eye on algae levels within the tank, especially if the betta tank is near direct sunlight. Monitor the water temperature during hot days, especially in warmer climates.

Prevent injuries to your betta

Buy a heater with a built-in plastic guard, so your betta won’t get burned. A built-in thermostat on the heater is a good idea to make manual temperature inspections easier. 

When placing a heater inside the tank for the first time, ensure your betta is temporarily housed in a separate tank or container. 

Allow the water to warm up to 78-80 degrees Fahrenheit and position decorations around the heater, so it is hidden from your betta to discourage playing around the heater. 

Sometimes bettas can be mischievous and end up lodging themselves between the tank and the heater. 

If this occurs, it may be difficult for bettas to swim free and require some help. Keep an eye on your feisty betta to ensure this does not occur.


Bettas are tropical fish and cannot handle too cool or too hot water temperature changes. For betta fish owners that live in colder climates, it can be a harrowing experience if the tank gets too cold. 

Betta fish’s immune system cannot handle fluctuations and will weaken over time. Diseases such as fish rot or ich can set in and ultimately lead to death due to weakened immune systems. It is essential to pay top priority to the aquarium temperature.

Whatever method you choose, make sure that it is a safe alternative and that it gradually increases the aquarium to the desired temperature. 

Bettas thrive when their environment stays consistent and get too stressed if the tank temperature becomes too hot or too cold. 

If the water is too cold, bettas can become lethargic, lack appetite, and have a slow metabolism, weakening their immune system. 

If the water is too hot, the oxygen in the tank decreases and bettas swim erratically in the tank and become too stressed out. 

A stressed-out betta is an unhappy betta. To keep your betta happy and healthy, the first step is ensuring its water temperature stays consistently warm.