Betta Fish

June 19, 2026 · Updated July 3, 2026 · 2 min read

A betta (Betta splendens) is a tropical labyrinth fish that needs a heated, filtered tank of at least 5 gallons, water at 78–80°F and pH near 7, and a meat-based diet. Males are territorial and kept alone or with a few careful tankmates.

The betta (Betta splendens), or Siamese fighting fish, is a tropical labyrinth fish from the slow waters of Southeast Asia. It breathes air at the surface, which is why it survives in tiny containers in stores. Surviving is not thriving: a betta needs a heated, filtered tank to live a full life.

Tank and water

A betta needs at least 5 gallons, heated to 78–80°F, with a gentle filter. Across 542 real betta tanks in the AquaGauge dataset (July 2026 snapshot), the median is 10 gallons and 92% are 5 gallons or larger. Keep pH near neutral (6.5–7.5); stable water matters more than a perfect number. The reference database FishBase documents a tolerance range of 24–30°C and pH 6.0–8.0 for Betta splendens.² See the full data in what size tank does a betta need, a head-to-head in 5-gallon vs 10-gallon betta tank, and safe ammonia & nitrate levels from 125 tanks.

Diet

Bettas are carnivores. A quality betta pellet is the staple, with frozen or live bloodworms and brine shrimp for variety. Feed a small amount once or twice a day, and skip a day a week. They do not eat flake meant for community fish well, and they cannot live off plant roots.

Temperament and tankmates

A male betta is territorial. It is kept alone, or with a few calm, non-fin-nipping tankmates in 10 gallons or more — bottom and mid dwellers that ignore it, never fin-nippers or bright long-finned fish. The compatible and incompatible species (from our compatibility model) are listed below. Plan a specific tank in what fish can live with bettas. Seriously Fish puts it bluntly: ornamental bettas are “best kept alone” and “not recommended for the standard community aquarium.”³ The classic aquarium author William T. Innes made the same point a century ago: “Betta, the Siamese Fighting-fish, can be kept with other fishes as it fights only its own kind.”¹ Two males, though, cannot share a tank: “Unfortunately males cannot be left together, as they tear each other’s fins badly.”¹

Lifespan and health

A well-kept betta lives 3 to 5 years. Most early deaths trace to cold or unstable water (no heater), an uncycled tank, or overfeeding. A heater, a filter, a cycled tank, and a varied diet cover the basics.

Varieties

Bettas are sold in many fin and color forms: veiltail, halfmoon, crowntail, and plakat (short-finned), among others. The care is the same across forms; long-finned types are more prone to fin damage from sharp decor or strong flow.

By Yevhen Bulhakov · fishkeeper & founder, reviewed against real-tank data.
Freshwater aquarist of 8+ years.