What is the Best Aquarium Size for Betta Fish?

A Comprehensive Guide to Appropriate Aquarium Sizes to Let Pet Bettas Thrive

What is a Betta Fish?

A domestic betta is an ornamental Betta splendens that has been selectively bred for aesthetic purposes. Reaching only about three inches in length as an adult, this fish is commonly kept in private and home aquariums and is perhaps one, if not, the most popular aquarium fish in the world. Domestic bettas are selectively bred predominantly from wild-type Betta splendens, originating from Thailand. This is where the betta also gets its other popular name, the Siamese Fighting Fish. Bettas live for approximately 2-3 years but can live much longer with exceptional care.

Why are Bettas so Popular?

Bettas are extremely popular fish due to their extensive forms of coloration that resulted from selective breeding. In addition, many people who encounter bettas find them very investigative and personable. Alongside this, bettas have a retail selling point of being able to thrive within small volumes of water. In reality, it is not the case, as it leads to poor welfare implications for bettas due to inconsistent water quality, lack of environmental enrichment, and limited space to perform natural behaviors.

 

Aquarium Sizes Appropriate for Bettas

2.5-Gallon: 

Standard dimensions are 12"(L) x 6"(W) x 8" (H). A 2.5-gallon aquarium should be the absolute minimum for just a betta. Keeping fish in small aquariums has its risks due to instable water parameters and lack of swimming space. With bettas, the absolute minimum water volume to have a full range of motion and perform natural behaviors without interference is about 10 liters, or 2.5 gallons of water. To increase environmental stability, if you are keeping a betta in this aquarium size, it should have a deeper substrate (2-3"), a small sponge filter, and plenty of easy, fast-growing, live plants.

We actually do not recommend a 2.5 gallon because chances are your water parameters will not stay consistent. This means you will have to do more routine water changes and maintenance to ensure that your betta remains healthy.

5-Gallon:

Standard dimensions for a 5 (5.5) gallon aquarium are 16" (L) x 8" (W) x 10" (H). This is the preferred minimum for a betta aquarium. With this tank volume, the available water volume and space is much better for the fish and allows for better expression of natural behaviors. 

Bettas cannot have any fish tank mates in this volume size due to the space, however, one nerite snail, or a few ramshorn snails is adequate for eating algae.

10-Gallon:

The dimensions for a standard 10-gallon aquarium are around 20" (L) x 10" (W) x 12" (H). This is the first aquarium volume on this list that is appropriate for the creation of a community aquarium. Your individual betta can live with compatible tank mates such as Pygmy Corydoras and Amano Shrimp. This tank volume is a community-popular minimum tank size for bettas.

20-Gallon (Long) & Greater Volumes

Although bettas can live and thrive within a 20-gallon high aquarium, the 20-gallon long is a better choice for bettas and the compatible tank mates that can coexist with bettas in a community set up. The dimensions for a 20-long are 30" (L) x 12" (W) x 12" (H). Tank mate options such as Panda Corydoras and Silvertip Tetras will be perfect additions to your aquarium. Keep in mind that tank mates are entirely optional and do not guarantee the welfare of your betta. Even in larger aquarium volumes.