Koi Carp

Apr 28, 2026 | Cold Water

koi-carp-swimming-lake

Koi Carp Overview

Scientific Name: Cyprinus carpio
Origin: East Asia, domesticated from wild carp in Japan
Adult Size: Up to 90 cm (around 35 inches)
Temperament: Peaceful and social
Difficulty Level: Intermediate to advanced
Tank/Pond Size: 1000L+ (or outdoor pond)
Temperature: 15–25°C

Koi Carp are large, ornamental freshwater fish famous for their vibrant colours, elegant patterns, and long lifespan. They are peaceful and social, thriving in groups and forming a striking focal point in ponds or very large aquariums. Due to their size and care requirements, Koi Carp are best suited to intermediate or advanced aquarists with access to a suitably large tank or pond.

Aquarium Requirements for Koi Carp

Koi Carp require spacious, well-filtered water environments to thrive.

Typical conditions include:

  • Tank/Pond Size: 1000 litres or larger recommended (ponds preferred)

  • Temperature: 15–25°C

  • pH Range: 7.0 – 8.0

  • Filtration: High-capacity filtration with strong water movement

  • Aquarium/Pond Type: Open, outdoor ponds or very large indoor aquariums with space to swim

Koi Carp need stable water quality and plenty of swimming room. Regular pond or tank maintenance is essential to prevent stress and disease.

Feeding

Koi Carp are omnivorous and require a varied diet to stay healthy and colourful:

  • High-quality koi pellets or flakes

  • Fresh vegetables like peas, lettuce, and spinach

  • Occasional treats of live or frozen foods like bloodworms or daphnia

Feed 1–2 times daily, adjusting portion sizes based on water temperature and fish activity. Avoid overfeeding to maintain water quality.

 

Behaviour and Tank Mates

Koi Carp are peaceful, social fish that enjoy living in groups.

  • Temperament: Calm and friendly, often recognizing their owners

  • Tank/Pond Mates: Other koi or large, peaceful fish species; avoid aggressive species

  • Social behaviour: Thrive in groups; interactive and active throughout the water column

Their size and friendly nature make them an impressive and engaging addition to ponds and large aquariums.

Setting Up Aquarium/Pond

To keep Koi healthy and happy:

  • Use a pond or large aquarium (1000L+) with open swimming areas

  • Ensure high-capacity filtration to handle waste and maintain water quality

  • Maintain stable water parameters with regular testing and partial water changes

  • Provide some plants or shaded areas for cover, but allow plenty of open space

  • House in groups to encourage social behaviour

Koi at Smith’s Aquatics

At Smith’s Aquatics in Stockton-on-Tees, we occasionally stock Koi Carp, showcasing their vibrant colours and patterns.

Our team can help you with:

  • Choosing healthy fish

  • Planning a suitable pond or aquarium setup

  • Selecting compatible tank mates

  • Advice on feeding and maintenance

If you are interested in keeping Koi Carp, visit our store to speak with our aquatics team and learn more about these impressive ornamental fish.