Create the perfect koi carp aquarium: advice, equipment and maintenance for healthy fish

Preparing an aquarium for Koi may seem a daunting task. However, with the right advice, the right equipment and rigorous maintenance, it is possible to create a healthy environment for these magnificent fish. Native to Asia and symbolising virility and love, the koi carp, or Cyprinus carpioKoi ponds deserve your full attention. In this publication, I'll guide you through the process of creating the ideal pond for your koi to ensure their longevity and well-being.

Introducing koi carp

Koi carp are renowned for their popularity in Asia, particularly in Japan, China, Korea and Vietnam. Originally bred in Japan, this variety of carp belongs to the same species as the common carp. It is distinguished by its barbels and bright colours.

In terms of morphology, koi carp have an ovoid shape and can reach between 60 and 90 cm longwith a weight between 5 and 8 kg. Some of the rarer ones can even measure up to 1.20 m! Females are generally larger than males, making sexual dimorphism easy to observe.

These fish are very hardy, with an average lifespan of 50 years. However, some Koi can live even longer under optimum conditions. Being gregarious by nature, koi carp prefer to live in groups and swim in shoals.

The different colours of koi carp

One of the most fascinating features of koi carp is the diversity of their colours. There are more than 80 varieties26 of which are fixed, while the others are the result of cross-breeding and are known as variations. The most common colours include :

• Red
• White
• Black
• Yellow
• Cream
• Orange
• Brown
• Grey
• Silver/Platinum
• Gold

The patterns are equally varied, including Kushibeni, Tancho, Hikari, Matsuba, Mono, Hi and Aka. The Tancho variety is particularly popular because its colour is reminiscent of the Japanese flag.

Pond size for koi carp

Koi thrive in large basins or ponds and are not suited to life in a traditional aquarium. To ensure their well-being, it is advisable to provide them with a tank with a minimum depth of 1.50 m and a water volume of at least 1000 litres per adult fish.

In general, a 20m³ tank is recommended for several fish. For rearing six koi, a pond of at least 5,000 litres is ideal. Such an environment allows the fish to swim freely and maintains a healthy ecosystem.

Number of koi carp	Recommended volume
1	1000 litres
6	5000 litres
10	10000 litres

Water quality is vital. A filter and pump are needed to keep the water clean and oxygenated. The water should be partially renewed every six months, at a rate of about a quarter of the total volume.

Koi carp menu

Koi carp are omnivorous, with a vegetarian tendency. It feeds mainly on floating pellets, but also on live food such as worms or insects during the warmer months. Vegetables complete its diet. Here are a few examples of foods for Koi carp:

1. High-quality floating granules
2. Live food (worms, insects)
3. Vegetables (buy, lettuce, spinach)
4. Seaweed

The frequency of feeding depends on the temperature of the water. Between 20° and 27°C, they can be fed up to 4 times a day. However, below 7°C, they stop eating and go into hibernation. I remember once forgetting to reduce the rations of my koi carp as winter approached... and they were sulking!

Co-existence with other fish

Koi carp are peaceful fish, which means they can easily cohabit with other species. Their ideal pond mates include :

• Tench
• Sturgeon
• L'ide mélanote
• The sterlet
• The stud

The presence of koi carp has a positive influence on the behaviour of other fish in the same area. basinThis creates a harmonious atmosphere. However, be careful to avoid small fish that could become easy prey.

As a pet shop floor manager, I've often seen customers fascinated by a well-stocked pond. A good mix of species not only beautifies the pond, but also promotes a balanced ecosystem.

Conclusion

Creating a Koi aquarium requires careful planning and a long-term commitment. From fish selection to habitat conditions, every detail counts to ensure their well-being. Koi are incredible fish that deserve the best, and with the right information, you can provide them with an optimal and sustainable environment.