Betta spl. male giant koi - Betta Fish for Sale UK

Koi patterning on a giant frame is one of the most sought-after combinations in the modern betta hobby, and that is exactly what this listing offers: a male Betta splendens from the giant koi line, growing to around 8 cm where ordinary males stay smaller. The marbled, koi-style blocks of colour that give the strain its name continue to shift and develop as the fish matures, so no two individuals ever wear quite the same pattern. We rate him moderate care, which makes this a fish for keepers who already run a stable, heated aquarium and want one spectacular centrepiece rather than a crowd.

Temperament-wise our records are blunt: this is an aggressive strain, and he does best housed alone. Snails usually pass beneath his notice, and some larger, calm shrimp may coexist in a heavily planted layout, though there is a real chance they end up eaten. Other male bettas are completely off the table, as are fin-nipping species, territorial or aggressive fish, long-finned tank mates that can trigger flaring, and anything small enough to be bullied. He occupies the top region of the aquarium, so prioritise surface space and gentle flow over depth when planning his home.

Day to day he is a straightforward fish to run. Feed a protein-rich carnivore diet in small portions — a larger betta works through food quickly but still does best with measured meals — and hold the water inside his 1–15 dGH hardness band, which most UK supplies sit within comfortably. A reliable heater matters more than any other equipment, because the 24–28 °C requirement does not pause in a cold snap. Acclimatise him slowly on arrival, give him a day of quiet before bright lights and visitors, and within a week he will be patrolling the front glass at feeding time. Three years is the typical lifespan on his record, and consistent water is what gets him there.

Giant Koi betta care at a glance

• Maximum adult size: around 8 cm
• Typical lifespan: about 3 years
• Care level: moderate
• Temperament: aggressive — house singly
• Water temperature: 24–28 °C
• pH range: 6.0–7.5
• Hardness: 1–15 dGH
• Minimum aquarium: 20 litres
• Diet: carnivore — protein-rich foods
• Swimming zone: top of the tank

Buying your Giant Koi male in the UK

Because koi marbling is individual, the fish that arrives will carry its own one-off pattern rather than matching a stock photograph exactly — part of the appeal of the line. He can turn territorial when breeding, so have a solo 20-litre-plus setup heated to 24–28 °C ready before he lands. Your order travels with a licensed live-animal courier and is covered by our live arrival guarantee.