About Mujimono Koi

Expertise, guidance and quality products for novice and serious koi hobbyists in the UK

Who Am I?

Mujimono Koi is a family-run business based in Nottinghamshire, England, and led by award-winning koi carp hobbyist Mark Stirzaker.

Who I Help

Whether you’re a seasoned hobbyist or a novice building your first pond, I’m on hand to recommend quality products and offer advice.

Me at the National Koi Show in 2017 with my two sons


My name is Mark Stirzaker and I’m a general enthusiast with over 30 years experience in keeping koi. Here on the Mujimono Koi shop you can buy quality equipment and accessories for your ornamental pond, and if you’re unsure what you need, you can contact me.

I built my first pond in the early ’90s, and I’m on my third pond now, which I’ve had for over 20 years. A lot of koi ponds start out as not much more than a hole dug in the ground with liner, which is considered old-fashioned and an entry-level budget set up by today’s standards. Back when I started this hobby, there was no internet as a free source of information. There were just books and lots of trial and error. I’ve worked hard to acquire knowledge over these last few decades and my aim is save you money and hassle in the process of embarking on this worthwhile and rewarding hobby.

Photo of Mark Stirzaker from Mujimono Koi
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)
Photo of Mujimono Koi exhibting at the Great British Koi Show (Newark)

I’ve taken my hobby to a level where I’ve been showing my fish at different koi shows across the UK for several years. In 2020, I won a Grand Champion B award at a very well-attended photographic show. I’ve got a trophy cabinet… not as big as some trophy cabinets, but at least I’ve got the award!


Receiving an award at the National Koi Show in 2017


To reach a competitive standard and maintain the fish year after year is a testament to the koi keeping abilities of all the people I meet at exhibitions up and down the UK. The work that goes on behind the scenes is huge, and includes keeping the water quality correct, conditioning the fish for a show, controlling the parasites, making sure the whites (which in Japanese is called shiroji) are as white as can be, and making sure the fish skin colors are vibrant.

These factors are all controlled via water quality, different types of food to enhance the white or the colors, as well as considerations such as the transportation of the fish to the shows to keep them safe and calm. If there’s one thing koi like, it’s stability, and that is a factor as part of transferring the fish from the transport medium to the showback pond for the duration of the event – usually a weekend. Showing your fish is quite an in-depth process!

Pure Japanese Bloodlines

I’ve always wanted to try to breed fish which I was successful at two years on the trot, hence the knowledge I’ve gained over the years which has contributed to the successful breeding of fish. In 2023 I participated in three shows, two of which involved successfully selling fish. After talking to me, knowledgeable koi hobbyists can see that I’m offering quality fish at a much more reasonable price compared to those imported from Japan.

There is no crossbreeding in any of Mujimono’s bloodlines. If we breed a female koi, the males come from the same koi farm in Japan, meaning any customers have a good idea of what the future of that fish will be. If there was to be a mixing of the bloodlines, there is less guarantee in what a Mujimono fish is going to turn out like several years down the road.

Koi carp pure Japanese bloodlines
Photo of Karashigoi koi fish from the Super Mango bloodline

Super Mango Bloodline

Our Karashigoi are from a world famous Super Mango line which are bred by Sakai ff.

We were very lucky to source the parents and have been successful with our spawning. This bloodline is slightly different from other breeders Karashigoi, the main characteristics tend to be a fully body shape, please note it seems more and more Japanese breeders have now introduced the super mango line into their own Karashigoi spawning

Super Mango Karashigoi are now used by many Japanese breeders because of their superior body shapes. A must for any single-coloured koi enthusiasts!

Koi Breeding Facility

Our goal is to supply koi to hobbyists at an affordable price without sacrificing quality.

I have a breeding facility in a polytunnel containing three ponds sharing the same water volume all filtered via one system. When you have fish at different sizes, the big fish tend to push the small fish out, meaning the small fish never thrive. For this reason, the water turnover in each pond is slightly different to keep the different sized fish separate for one another and maintain their growth rate. Once the fish have bred and spawned, we can develop the fry into sellable fish.

Mujimono koi Japanese Chagoi bloodline fry
This is our three-pond breeding facility where we grow koi fry available for sale at several koi shows throughout the UK

Karashigoi and Chagoi Breeding

The video shows the development of the Karashigoi and Chagoi fry in the breeding facility.

Chagoi are bred from our Marusei Parents. Marusei is considered to be the best breeder of Chagoi in the world, which have jumbo genetics.

Our Karashigoi are bred from our Sakai ff Super Mango line.


Talk to Me For Advice & Info