Variety of Betta
Koi betta
Betta splendens
One of 8 varieties of Betta splendens · See all varieties →
FreshwaterFish
Varieties · Betta splendens
See all 8 →
Care at a glance
- Temperature
- 72–86°F
- 22–30°C
- pH
- 6.0–7.5
- Adult size
- 3 in
- 7.5 cm
- Minimum tank
- 7 gal
- 25 L
- Temperament
- Aggressive
- Social behavior
- Solitary
- Own kind
- One male per tank
- Tankmates
- With caution
- Swim level
- Middle
- Difficulty
- Beginner
- Breeding
- No record
- Rarity
- Very common
- Family
- Osphronemidae
Overview
Bought for a pattern that will not hold still, because koi bettas are marbles and the blotches move over weeks and months. The fish in the cup is rarely the fish you have a year later, and shops price on how clean the pattern looks that day. Galaxy koi, candy koi and nemo koi are trade labels for color mixes rather than separate strains. Nothing about keeping one differs from any other betta.
In the wild
Thai breeders built the koi look on the marble gene. Marbled fish were crossed onto pale cellophane and white stock until red, black and orange sat on a light body. The koi name is borrowed from koi carp and spread with the export of Thai show stock. No individual originator is documented, and no wild betta carries the pattern.
Good to know
Marble is described in hobby genetics as a transposable element, a piece of DNA that changes position. When it lands in a pigment gene, color switches off in that patch, and when it leaves, color returns, which is why the pattern keeps rearranging for the life of the fish. It moves in eggs and sperm too, so koi pairs throw fry in patterns neither parent shows. Which gene it sits in is not settled in published work.
Did you know
The marble gene reached the hobby from an Indiana prison, where an inmate named Orville Gulley bred bettas in peanut butter jars. He was chasing a black butterfly betta and got marbling instead. Koi patterns are built on that same gene.
Common questions
Is a Koi betta a different species from the Betta?
No. A Koi betta is a variety of the Betta, Betta splendens, and it wants the same tank, water and food as the species.
What size tank does a Koi betta need?
A Koi betta needs at least 7 gal (25 L). It spends most of its time in the middle.
How big does a Koi betta get?
An adult Koi betta reaches about 3 in (7.5 cm).
Related species
2.4 in (6 cm)11 gal (40 L)72–82°F (22–28°C)Emerald betta
Betta smaragdina
2.4 in (6 cm) · 11 gal (40 L)
3.9 in (10 cm)20 gal (75 L)72–79°F (22–26°C)Brunei beauty betta
Betta macrostoma
3.9 in (10 cm) · 20 gal (75 L)
- 2.2 in (5.6 cm)26 gal (100 L)72–81°F (22–27°C)
Gladiator betta
Betta gladiator
2.2 in (5.6 cm) · 26 gal (100 L)
3 in (7.5 cm)20 gal (75 L)72–81°F (22–27°C)Compuncta betta
Betta compuncta
3 in (7.5 cm) · 20 gal (75 L)
- 2.9 in (7.3 cm)16 gal (60 L)72–81°F (22–27°C)
Aurigans betta
Betta aurigans
2.9 in (7.3 cm) · 16 gal (60 L)
- 2.8 in (7.2 cm)21 gal (80 L)72–81°F (22–27°C)
Pardalotos betta
Betta pardalotos
2.8 in (7.2 cm) · 21 gal (80 L)