How Many Gallons Does A Betta Need

Last Updated on October 8, 2020

An experienced betta fish owner can use a minimum of 2.5 gallons fish tank for a betta fish. A small container, however, is not a suitable home for a betta to live in. You will want your betta fish to thrive and not just survive.

The size of a betta fish tank plays a major role in its overall health. Small tanks are very difficult to balance. The smaller you go, the more waste builds up and faster, requiring more frequent water changes.

A beginner in the betta fish keeping hobby will be more successful with a minimum of 5 gallons to house a single betta fish.

The reason for this is that the larger water volume will not have water parameters fluctuate suddenly. This will give the beginner more wiggle room to maintain a healthy environment for a betta fish.

Factors to Consider When Taking Care of Your Betta in the Tank

Size of Tank

A 5-gallon tank is the minimum recommended tank size for beginners who want to take care of a betta fish. This has a larger water volume which will not have water parameters fluctuate too fast. Sudden changes in water parameters cause stress in fish. Stress will make your betta more prone to disease.

The bigger size of the tank will also give more room for your betta to swim around. This will also give you more space for live plants, driftwood, rocks, and other tank mates. Having a larger capacity in a fish tank will also allow you to put in the important heater and filter when keeping betta fish.


Installing a filter is also important to keep the water in your betta fish tank as clean as possible. The filter will also house beneficial bacteria, which will prevent the accumulation of harmful substances such as ammonia and nitrite.

The filter also provides water surface agitation, which allows gas exchange. Oxygen comes in from the atmosphere as carbon dioxide escapes the water. Your betta fish also have gills that it can use to absorb the dissolved oxygen in the water column.

A small tank can not have a filter installed properly. A filter in a small tank will create too strong a flow that will stress out your betta fish. Betta fish prefer gentle flow. A sponge filter with an air stone is a great option. Connect it through an airline tubing to an air pump. The air pump blows air into the water causing an upward sucking current inside the sponge filter.

Filter sponges will trap debris such as fish poop and uneaten food. Clean the sponge once a month by squeezing it several times in water treated with a water conditioner. Do not use tap water to rinse a sponge filter because this will kill the beneficial bacteria colony in it.

Shape of Tank

The shape of the tank is also a factor to consider. Betta fish have a labyrinth organ that allows them to absorb oxygen from the air they gulp from the water’s surface. This evolutionary trait has allowed betta fish to live in shallow water with not much-dissolved oxygen.

A tall container such as a vase is not a healthy choice for betta fish because it will require them to exert more energy just to go up and down the water column. A 5-gallon fish tank with a rectangular shape is more suitable. This allows a wider surface area where air and water meet.

But for a period, you can put betta fish in a vase when cleaning your tank or isolating the sick ones.

The elongated shape will not require your betta to spend too much energy as it moves up and down the aquarium.


Use an aquarium heater to provide the optimal temperature range. An aquarium thermometer is important so you can track the temperature in your fish tank. Place it at the opposite end of the fish tank to determine the water temperature as far from the heater as possible. This will ensure that it heats evenly the water throughout the betta fish tank.

Make sure you submerge the heater fully into the fish tank. A small tank will not allow the accommodation of generic heaters. This is the reason we always recommend a 5-gallon tank.

A small container with the heater will cause the water to increase temperature fast and also cool down fast, making your heater do more work. This will require more electricity. It can also take up so much space that your betta is always dangerously near the heater.

Water Temperature and Quality

betta fish water quality

A heater is essential to provide the optimal temperature preferred by betta fish. Ideally, the water should be between 78 to 80 degrees Fahrenheit (25.5 to 26.5 degrees Celsius) for a betta. Betta fish are tropical and may go into shock at temperatures below 74 degrees Fahrenheit, though it is more common for them to react poorly when temperatures drop below 72.

Low temperatures will make your betta fish lethargic, lose appetite, and more prone to disease. The high temperature will speed up its metabolism and cause it to age faster because of a decreased lifespan. Keep the temperature in the optimal range and this will give you peace of mind that your betta fish can thrive in its environment.

Related: How to Warm Up a Betta Tank Without a Heater?

Water quality plays a major role in the health of your betta fish. Betta fish will live its entire life in the water you provide it so make sure your parameters are always great.

Ammonia and Nitrite should be at 0 ppm. Nitrate should not exceed 20 ppm. pH should be 6.5 to 7. You can regularly use a test kit to check your water. Do this every two weeks or during your weekly water change.

We recommend partial water changes to avoid a big alteration of water chemistry. 15-20% partial water change every week is good practice to follow. Always use a water conditioner for your betta fish tank. This will neutralize chlorine, chloramine, and heavy metals from tap water.


The world of aquascaping has piqued the interest of many hobbyists. Live plants, driftwood, and rocks arranged artistically to emulate nature allows you to mimic the environment of fish.

Related: Are Live Plants Good for Betta Fish?

Use rocks and driftwood which are not sharp. Sharp objects can harm the delicate fins of betta fish. If you use imitation plants, then always choose the materials well. Silk based artificial plants are better than plastic ones.

We should always check decorations before being introduced into the fish tank. Do not use sharp objects. Avoid those that have an artificial coating of paint and glaze because you can not be sure if it’s safe for your betta.

Best Betta Tanks

Fluval Edge 2.0 Aquarium Kit

The 12 Gallon Fluval Edge 2.0 Glass Aquarium Kit by Fluval offers a stylish and modern design. This is a great way to display your betta fish.


  • Unique glass aquarium with a sleek and modern design.
  • Unique top-sided viewing experience that is enhanced with the LED lighting system included.
  • 6000K integrated LED replicates natural sunlight and promotes plant growth and vibrant fish with a 120 degree light dispersion for wider coverage.
  • Includes a built-in aquarium filter with an adjustable flow which is great for Bettas.


  • The opening of the tank is smaller than normal, so maintenance and cleaning will require a little more work.
  • Its sealed no-lid design should not be filled completely to allow the betta access to more surface air.
  • A small opening will limit the options of decorations you can use in terms of size.
  • It doesn’t have a built-in heater.

Scapers 10 Gallon Tank Starter Kit – Dennerle

The Scapers 10 Gallon Tank Starter Kit by Dennerle will encourage beginners to get into the hobby of betta fish keeping and taking care of aquatic plants. This will allow you to provide a more natural habitat for your betta.


  • Beautiful looking rimless glass aquarium.
  • Nano 5.0 5W LED light has a 6500K color temperature to mimic natural sunlight with a 500-lumen output to provide enough light for the growth of a tank full of plants.
  • Nano-sized corner filter that turns over 150 liters per hour to give you enough flow and filtration.
  • Soil substrate included for providing nutrients for aquatic plants.
  • C02 system and fertilizer included providing an environment for aquatic plants to thrive.


  • This may overwhelm a beginner, but a little research online will ease the worries of starting out.
  • It does not include a heater in the kit. You need to purchase this separately, especially for a betta.
  • Does not have a lid that covers the top completely. Betta fish may jump out of a tank so you need to take this into consideration.

Trigger Systems Sapphire ATO Reservoir Tank – 10 Gallon

This is actually a reservoir tank for top off water however it can also serve as a home for a betta fish. We can also use this as a breeding tank. Once the betta fry is free-swimming and we remove the parents this can also be a grow out tank.


  • Has a lid to prevent evaporation and heat to escape


  • It is made of acrylic which, unlike glass, is prone to scratches.

Related: What is the Best Betta Fish Tank Available?