Visiting Hobbyist 2024: Ryuji Kawakami (Ibaraki)

Even male Koi can grow big and win at Koi shows!　Taking on the All Japan Koi show in a 1.8 ton FRP tank.

Hobbyist

Every Nishikigoi lover dreams of a large pond. However, for many people, the dream of aiming for 90cm with a small number of fish, one fish per 3 tonnes of water, or even one fish per 5 tonnes of water, is just that – a dream. In reality, in addition to the issue of money, many enthusiasts choose to use ready-made ponds, considering the ease of installation and removal.

Mr. Kawakami’s breeding environment consists of two FRP tanks with a total capacity of 1.8 tonnes, and a 500-litre container. You might expect that the main focus of his Koi collection would be small to medium-sized Koi, but in fact, seven of the Koi in one of the FRP tanks are over 60cm in length, with the largest one being in the high 70cm range. What’s more surprising is that all of them are male. After purchasing them as Tosai, he deliberately kept the Koi that turned out to be male and is raising them at home.

We asked him about his unique way of enjoying Koi, saying ‘Even male Koi can grow big and become beautiful’.

The same amount of food is fed year-round, even in winter

Frequent cleaning and Wakishimizu are also very effective

This is actually the second time that Mr. Kawakami has appeared in an article in this magazine. His first appearance was in 2007, when he was introduced in the popular series ‘Let’s Enjoy a 3.3m2 Pond!’, as a hobbyist with about 5 years of experience in keeping fish. At the time, he was keeping fish in one FRP tank and a 90cm tank, and the FRP tank is still in use today.

The difference from 17 years ago is that we have added one more FRP tank of the same type and installed a Wakishimizu 10 model. We have also placed a 500-litre container for Tosai and covered it with a plastic greenhouse that can hold all of these. The standard water capacity of the FRP tank we are using is 1.5 tonnes, but by changing the position of the overflow pipe, we have increased the capacity to 1.8 tonnes. The water level has risen as a result, so a net to prevent them from jumping out is essential.

Ryuji Kawakami (left) and his friend Satoshi Mitabe.
A plastic greenhouse that can hold two FRP water tanks and containers, etc.

The level of the Koi has improved significantly as a result of the improved facilities. One of the two FRP tanks is home to relatively large Koi that are four years old or older, and this is where the Koi that won prizes at the Kanto-Koshin District Koi Show, as well as a Kohaku that came back from Handler Bando Koi Farm after winning the 70bu Male Kokugyo Prize at the 54th All Japan Koi Show. All of these are male Koi.

One of the reasons Mr. Kawakami focuses on breeding male koi is because of space issues. The 2.4m x 1.2m, 60cm deep FRP tank is not small, but it may be a little cramped for breeding large females.

Mr. Kawakami says, ‘If you want the female to grow to 85 or 90 cm in the end, it would be a waste to keep her in this pond.’ However, they are not keeping the male small just because he is a male. Rather, the aim is to allow them to grow large and gain volume, but another reason for selecting males is that ‘even if you feed them a lot and make them big, the male’s body shape is less likely to collapse’. All seven of the 4-year-old and older males have good body lines, and their body shapes are not inferior to the females. Mr. Kawakami himself says that he ‘never thought it would be possible to raise a male carp to have a body comparable to that of a female’, and the reason for this is a method of raising the fish that cannot be said to be entirely in accordance with the theory.