Do Betta Fish Need A Heater? (Complete Guide)

If you’ve just bought an aquarium you may be wondering do betta fish need a heater?

If you’re on the fence about buying a heater then after reading this article you’re going to find out:

  • The optimal temperature your betta fish thrive in.
  • Why temperature fluctuations are so dangerous.
  • The fatal consequences of water that is too cold.
  • How you can keep your tank warm if your heater breaks.

You can skip to any information you want using the links below!

Do Betta Fish Need A Heater?

You may have seen the pictures of bettas in tiny fish bowls or sometimes cups. And you may be questioning whether bettas need a heater or not. In 99% of cases, the answer is yes.

How Important Is A Heater For Bettas?

If you don’t have a heater for your betta then you should buy one ASAP. All fish are extremely sensitive to the temperature in their tank, and in particular, constant fluctuations. While a cold wind or draft may be a nuisance to you, over time they can prove fatal to your betta. In fact, avoiding temperature shock is one of the best things you can do to keep your fish healthy.

The only time you can get by without a heater is if the room your tank is in remains at a constant temperature. You may think your room does this. But have you taken into consideration that the temperature of your house drops at night, and in the winter?

Heaters for your fish tank aren’t expensive and they’re well worth the investment to keep your betta healthy.

(Here’s a helpful article explaining the dangers of temperature shock as well as the symptoms and how to treat it.)

What’s The Ideal Temperature For Bettas?

The ideal temperature for your betta is 78-80°F. This is the temperature that is going to help keep your betta in optimum health. However, bettas will remain healthy anywhere between 76-82°F. The danger comes when your temperature becomes too low or too high. If the temperature of your tank drops below 74°F or goes above 85°F then it’s going to severely impact your betta’s health.

What Will Happen If Your Betta Gets Too Cold?

When your fish is in water that is below 74°F you’re going to cause them serious distress and eventually they will die.

The first thing you will notice when your tanks temperature begins to drop is your betta becoming sluggish. This is because his metabolism is slowing down as he tries to conserve energy.

As your betta increasingly becomes more stressed you’ll notice him stop eating. The whole time this is happening his immune system is also weakening because of the added stress on his body.

You’ll begin to notice the color fading from his skin and scales.

He may try to stay near the bottom of the tank or where any heat is.

But, it won’t help. Now that his immune system is low he’ll be more prone to a bacterial or fungal infection.

Some of the diseases such as fin rot will be relatively easy to cure if you get the temperature back up and follow a proper care guide, like the one you can find here. Or they could get a disease which is more serious like dropsy.

As you can see, leaving your betta in a tank that is too cold is extremely cruel. And if your not 100% certain you can maintain a constant water temperature without a heater then you need to get one.

betta fish

What Will Happen If A Betta Gets Too Hot?

If you’re curious about what will happen when a betta gets too hot, then the truth is over 85°F you’re fish will slowly begin to start overheating.

The first signs you’ll notice is your fish swimming erratically. Fish are cold-blooded animals and can only stay at the same temperature as their surroundings. The added heat will give them more energy. This sounds like a positive but actually, it will cause your fish massive stress weakening their immune system.

If you’re tank is getting too hot there are solutions. One thing you can do is let a fan blow over the top of the water. This is going to cause evaporation to happen at a faster rate keeping your tank colder.

Why You Should Consider Getting A Bigger Tank

If you had a cup of boiling water or a bath of boiling water, what one would cool down first?

Obviously, the temperature of the cup would drop a lot quicker than the baths. And that’s the exact same reason you should consider a good size tank.

Even though the recommended minimum for bettas is 2.5 gallons, a smaller tank is more susceptible to faster, drastic temperature changes. (And they also need to be cleaned more regularly.) I personally would never go any lower than 5 gallons for a betta.

Once you start to get tanks that are 5 gallons or higher, it’s a lot easier for the tank water to stay at a constant temperature. Even if you have a heater in a 2.5-gallon tank a sudden drop in room temperature is still going to have a big effect on it.

How to Heat a Betta Fish Tank in an Emergency

If you have a heater for your fish tank, at some point there may be an emergency. The heater might break or there could be a power cut. Whatever it is, when the times come you may be wondering how you can keep your tank warm.

Once again having a bigger tank will benefit you in this situation. The water will take longer to cool down, giving you more time to come up with a solution. Some common solutions are:

  1. Turning up the heating in your house. This can work if you know it won’t be long before you can heat your tank again, or if you’re using a small tank. By heating your house, you’re going to stop the room temperature lowering the water temperature.
  2. Make sure you move your tank away from any windows and get it closer to the center of your house. Heat is lost through windows, so areas of your house near windows can often be cooler.
  3. However, if it’s a sunny day, and quite warm outside you might consider doing the opposite. Leaving your tank in the sun is going to heat the water up. Just make sure it doesn’t get too hot.
  4. Get some hot water and place it in a bag. (10% of the size of your tank should be enough). Make sure the bag is warm but not boiling. Take 10% of the water out of your aquarium and place the bag in. Then just let the bag float on the top of your tank.
  5. If your tank is open topped then you can place a towel over the top to help keep the heat in. This can also keep heat in when you do have a lid. Heat rises, and putting a towel over your tank is going to keep the heat in.
  6. On the subject of towels, you can also wrap towels around your tank to keep the heat in as well. While the sudden light change may stress your betta a little, it’s still not going to be as stressful as a water temperature drop.
  7. Try using other household items that create heat. For example, you could move a lamp near your tank and focus light on it, or you could aim a hairdryer at your tank. Obviously, these are short term solutions but they can be useful while you’re looking for a more permanent solution.
  8. Another great choice if your heater has broken is to wrap your tank in an electric blanket. Just make sure you’re monitoring the temperature of your tank carefully.
  9. Set up candles around your tank. Tea lights work best. If you put enough around your tank, the heat from the flames is going to be enough to keep the water in your tank warm.

These are just some of the ideas I’ve come up with off the top of my head. If you have any ideas you should try them too. The most important thing is to make sure you’re monitoring the temperature of your tank and making sure that it’s not rising or falling to significantly.

siamese fighting fish

How Long Will A Betta Survive Without A Heater?

There are so many different factors that go into whether a betta can survive without a heater. For example, if the temperature of your room is above 78°F then your betta is probably going to last a long time. But if it’s too cold or your betta is already sick then it can be a matter of days before your betta becomes extremely unhealthy. But once again there are so many factors that should be taken into consideration such as room temperature, the age of your betta, how healthy your betta is, how quickly the water temperature is dropping etc.

Do You Have A Better Understanding Now?

So, do betta fish need a heater?

After reading this article you should have a better understanding of why it’s so important for your betta fish to have a heater. Just as a quick reminder here are the most important things you need to know.

  • The ideal temperature for betta fish is between 78-80°F. This is the temperature in which they will really thrive. However, if your tanks temperature is between 74-85°F they will still stay healthy.
  • When the temperature of your tank drops below 74°F then your fish will start to suffer. His immune system will weaken and the most likely outcome will be a disease and then death.
  • If your tank goes over 85°F then your fish will start overheating, causing stress and eventually death.
  • One of the best ways you can keep your fish tank at a stable temperature is to get a bigger one (minimum of 5 gallons). When there’s more water in a tank it’s harder for the temperature to fluctuate as much.
  • If your heater breaks there are a number of things you can do to keep it warm. Such as floating a bag of hot water in it, wrapping it in an electric blanket and moving it somewhere warmer.
  • If your heater does break it doesn’t mean your betta will get sick straight away. There are a lot of factors that will also contribute such as age and the current strength of your bettas immune system.

If you need to know more about setting up a betta tank then check out this handy Betta Fish Tank Setup Guide!

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If you have any more questions feel free to leave them in the comment section below otherwise have a great day. And be sure to check out some of the other articles to make sure you’re giving your betta the best care possible.

  • Should You Leave Your Bettas Light On Or Off At Night? – Bettas are complicated fish. Their need for light is similar to our own. A common mistake many people make is giving their betta too much light or not enough, without even realising! This article will clear up once and for all how much light you should give your betta.
  • What it Means When Your Betta Is Swimming Erratically – Betta fish can swim erratically for a whole number of reasons. If you don’t know what the common signs of illness are in bettas then you should definitely check this article out. After all, it may help you diagnose a serious illness in the future!
  • Temperature Shock – Temperature shock can quickly become fatal if you don’t spot it early enough. Find out the different symptoms and causes of temperature shock and what to do about it.
  • Best Heaters For A 5 Gallon Tank – If you haven’t gotten a heater yet, now’s the time to do so. Check out the best heaters you can buy for a 5-gallon tank.

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