Betta fish can live with certain peaceful species in a tank of at least 10 gallons, but success depends on the individual betta's temperament, adequate space, and careful species selection.

Nerite snails are one of the safest tank mates. They are excellent algae cleaners, cannot reproduce in freshwater, and most bettas ignore them completely. Mystery snails also work well, though they are larger and produce more waste.

Amano shrimp and ghost shrimp can coexist with bettas in well-planted tanks that provide hiding spots. Some bettas hunt shrimp aggressively while others ignore them, so observe closely after introduction. Cherry shrimp are more colorful but their small size makes them a tempting snack for many bettas.

Corydoras catfish are peaceful bottom dwellers that stay out of the betta's preferred upper water column. Their armored bodies and calm demeanor rarely trigger betta aggression. Keep corydoras in groups of four or more in a tank of at least 20 gallons.

Kuhli loaches are nocturnal bottom dwellers that hide during the day and are rarely noticed by bettas. They need sand substrate, hiding spots, and groups of at least three.

Ember tetras and harlequin rasboras are small, fast schooling fish that work in larger tanks of 20 gallons or more. Avoid bright-colored or long-finned fish that bettas may mistake for rival males. Guppies, for instance, are a poor choice because males have flowing colorful tails that provoke attacks.

Never house two male bettas together or add tank mates to a tank smaller than 10 gallons. Always have a backup plan to separate fish if aggression occurs. Introduce tank mates before the betta when possible, as bettas are more territorial in established spaces. Watch feeding time carefully since bettas can become aggressive over food.