The Male Koi Siamese Fighting Fish (Betta splendens) is a highly prized variety of betta known for its distinctive marbled, multi-coloured patterns that mimic the look of traditional Japanese Koi pond fish. Characterised by patches of red, orange, yellow, black, and white, these fish carry a special “marbling gene” that can cause their unique colour patterns to shift and change over time.

Key Care & Aquarium Requirements:

• Housing: Minimum tank size of 15 to 40 litres for a single male. They should never be kept in small bowls or jars.
• Temperament: Highly aggressive and strictly territorial. Never place two males in the same tank, as they will fight to the death.
• Water Temperature: Strictly tropical, requiring a stable heater set between 22°C and 28°C.
• Water Flow: Minimise water movement. Use a gentle air-powered sponge filter, as strong power filters will exhaust and tear their long fins.
• Environment: A heavily planted aquarium with live foliage, smooth rocks, and driftwood helps mimic their natural environment and provides necessary resting spots near the surface.

Common Fin Variations:

Koi bettas are usually bred into distinct physical shapes:

• Plakat (PK): Short, traditional wild-type fins. They are highly active and less prone to fin damage.