Fishbowl Adviser

Do Betta Fish Need a Heater and Filter in Their Tank?

If you have a betta fish in your tank or are planning to get one, you need to make sure to set up your tank properly. And if you want to properly take care of your betta fish, you need to know whether or not your betta fish need a heater or filter in their tank.

Betta fish

Do Betta Fish Need a Filter in Their Tank?

In the wild, bettas live in shallow bodies of water (like rice paddies). During the drought season, wild bettas could end up in some murky puddle with little oxygen in them. Because of that, bettas have been able to survive in bad conditions through evolution, keeping their unique ability to get oxygen from the air of the water’s surface. But, betta fish are at their best in tanks that have filters. To thrive, bettas need to have clean water that requires filtration. Having high-quality water with a filter in place will make sure your bettas are at their best. And since bettas do best while living in stable water parameters, they enjoy living in filtered tanks.

Betta Fish Habitats Without Filters

Tanks of 2.5 gallons or less should not have a filter in them. In small tanks, filters can do more harm. Why is that?

Having filters in smaller tanks can cause very strong currents that can toss bettas around and make their environment stressful. And since bettas are not such strong swimmers, they will have mobility issues with these strong currents. But water quality can quickly decline in tanks without filters. The larger the tank, the slower the decline in water quality. Plus, smaller tanks are easier for regular maintenance.

Benefits of Having a Filter In a Betta Tank

Apart from allowing your betta to thrive, there are many benefits to having a filter in a tank. Here some of the most important ones:

  • Maintenance
  • Good Bacteria
  • Oxygenation
  • Waste Reduction

Filtered tanks are much easier for cleaning. With a filter in place, you won’t have to perform complete water changes and risk destroying any helpful microorganisms. It will be enough to perform a 30% weekly water change along with regular vacuuming of the gravel and algae cleaning up. This water change will take you about ten minutes each week for a 10-gallon tank, which is less of a hassle than completely changing the entire water in the tank with the fish and decorations and adding everything back again.

Filters will also help with the removal of excess food and feces, along with bad bacteria and ammonia. But, the beneficial microorganisms will accumulate in tanks and filter media, so you won’t risk providing an unhealthy environment to your fish. And filters will help oxygenate the tank’s water.

Do Betta Fish Need a Heater in Their Tank?

When people get betta fish for their tank, they don’t always think they need to get a heater, especially in small tanks or bowls. But even though most people are not aware, bettas are tropical fish and they need warm water to thrive in. The temperature they need is between 70 and 80 degrees. Ideally, the temperature will be around 78-80 degrees. This temperature will help make sure your bettas are in optimum health.

Putting a heater in your betta tank is a good idea when planning your tank arrangement. Bettas like to have a constant water temperature. Without the heater, the water temperature will be dictated by the temperature of the surrounding air, which can fluctuate throughout the entire day. If you keep the temperature of your room at these temperatures at all times, you don’t have to get a heater. However, if you can’t keep that temperature at all times, you must get a heater to make sure your fish have a proper environment.

Low water temperatures can be stressful for your bettas, and increase the risk of getting a disease and even premature death. Surviving isn’t thriving, and you shouldn’t risk your betta’s health. However, if you have a small tank, a heater can end up heating them too much, which can endanger your betta and kill it. It’s best to have a heater in a tank of 5 gallons or more.

What Will Happen If the Betta Gets Too Cold?

If the water temperature is below 74 degrees, it can cause a lot of stress to your fish and cause it to die. The first indicator that your tank’s temperature is low is noticing that your betta is starting to be sluggish. The metabolism of your fish will slow down while the betta tries to conserve its energy.

And as the water continues to drop, you will notice the betta will stop eating and the color from the scales and skin will start to fade. And he might try to stay at the bottom of the tank, to be close to the heat. But, while your betta is trying to get warm, his immune system will get weaker and weaker, leaving the fish prone to a bacterial or fungal infection. Your fish will be more prone to getting diseases and conditions like dropsy. If you’re not certain you can keep a constant temperature in your tank, you need to get an aquarium heater.

Siamese fighting fish

What Will Happen If the Betta Gets Too Hot?

If the temperature of your tank is above 85 degrees, your bettas will start overheating. Fish are cold-blooded animals and they will want to maintain the same temperature as their surrounding environment. Even though this sounds like a great thing, it will cause a lot of stress to your fish and leave their immune system weak.

However, if your tank gets too warm, there are some solutions that you can try. But, first, you need to notice the change in temperature and fish behavior. With regular use of a water testing kit as part of your aquarium maintenance, you can notice the changes. Or you can closely observe your fish and notice the change in their behavior. One of the first signs that your fish is overheating is that they will start swimming erratically. As for solutions, you can put a fan to blow at the top of the water and wait for evaporation that will keep the tank colder.


  1. How Should I Keep and Care for Siamese Fighting Fish? – RSPCA
  2. How to Take Care of a Betta Fish: History, Life Span, Feeding, and Tank Setup – PetMD


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