TankBud

Sims' betta

Betta simorum

Also known as Simorum fighter, Green dragon betta

FreshwaterFish

Sims' betta (Betta simorum)
The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature
73–81°F
23–27°C
pH
4.0–6.0
Adult size
3.5 in
9 cm
Minimum tank
20 gal
75 L
Temperament
Mostly peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Middle
Difficulty
Medium
Breeding
Bubble nester · Hard
Rarity
Rare
Family
Osphronemidae
Origin
Jambi and Riau peat swamps, Sumatra, Indonesia

Overview

Sims' betta is a large, mostly peaceful wild betta for a dim blackwater tank. It is best with a little experience.

Did you know

Sims' betta is named for the Sim brothers, Singaporean aquarists active in the wild-betta world. The plural Latin ending of simorum packs both siblings into a single name.

Caring for the Sims' betta

Give a pair of Sims' bettas a shaded, deep tank of at least 20 gal (75 L), with dense cover. Keep it dim and tannin-dark, with a dark substrate, leaf litter, driftwood and floating cover overhead. Fit a tight lid, since this fish is a strong jumper.

Sims' bettas need soft, acidic water at 73 to 81°F (23 to 27°C) and a pH of 4.0 to 6.0. Peat filtration and botanicals help hold the acidity. Feed them well with meaty foods, such as small live and frozen items, insects and good pellets.

Keep a single pair, or a group only in a big, heavily planted tank with room for each fish to hold territory. Rival males will squabble, and small or delicate fish can be intimidated. Choose tank mates carefully, and many keepers give them a species tank.

Unlike the mouthbrooding bettas, Sims' betta is a bubble-nester. The male builds a nest at the surface and tends the eggs, and breeding it is difficult.

Good to know

Betta simorum belongs to the family Osphronemidae, the labyrinth fishes, which breathe air at the surface through an accessory organ. It sits in the Betta bellica group, close to the slender betta but with a more sloping head and longer pelvic fins.

In the wild

Sims' betta lives in peat-swamp forest in the Jambi and Riau provinces of Sumatra. It stays among leaf litter in shallow, shaded blackwater that is extremely soft and acidic.

Common questions

What size tank does a Sims' betta need?

A Sims' betta needs at least 20 gal (75 L). It spends most of its time in the middle.

What temperature and pH does a Sims' betta need?

A Sims' betta is comfortable at 73–81°F (23–27°C) with a pH of 4.0–6.0.

What does a Sims' betta eat?

A Sims' betta eats meaty foods, such as small live and frozen items, insects and good pellets.

How big does a Sims' betta get?

An adult Sims' betta reaches about 3.5 in (9 cm).

How does a Sims' betta breed?

A Sims' betta is a bubble-nester, unlike the mouthbrooding bettas. The male builds a nest at the surface and tends the eggs, and breeding it is difficult.

Related species