As the summer season gets well under way, now is the perfect time to look at the different species of pond fish and koi that are available. We start with the most prized pond fish - the koi carp.
Koi carp (Cyprinus rubrofuscus) are probably regarded as the king of the pond fish and the fish that most pond keepers aspire to keep. Originally bred as a food fish as far back as the 5th century BC in China where no doubt different colour morphs naturally emerged, it wasn’t until the 1820s in the now synonymous region of Niigata in Japan that the colour morphs we see today started to be selectively bred. Even then, these amazingly colourful fish were relatively unknown to the outside world until 1914 when several colour varieties were exhibited at a show in Tokyo. Since then lots more colour varieties have been developed, below we look at some of the more popular ones you are likely to see at your local specialist Koi centre and explore the meaning behind their exotic sounding names:
First bred in 1888, this is one of the oldest and most popular varieties. Kohaku literally translates as ‘amber’ but if you break the character symbols down further you actually get ‘red and white’ which far more accurately describes these fish which have a white base colour or shiro with red markings over the top, known as hi. The size, placement and definition of these markings further breaks down the variety name for example if the red markings wrap around the belly of the fish, this would be called a Kohaku Makibara.
More commonly abbreviated to just Sanke, this variety was first exhibited in 1914 and is very similar to the Kohaku in that it has a white base colour with red markings but with the addition of black markings or Sumi. These black markings should be confined to the body of the fish, above the lateral line.
Again more commonly abbreviated to just Showa, this variety was first exhibited in 1927 during the reign of the Showa emperor, hence the name, this variety is in effect the mirror of the Taisho Sanke having a base colour of black with red (hi) and white (shiroji) markings.
These 3 varieties together are referred to as the ‘Big Three’ or Gosanke from which all the other varieties are derived from.
Tancho is the name given to any koi with a single red patch on its head, named after the national bird of Japan, the Tancho crane. This trait is not breed able and only occurs by chance in individuals of the above varieties, for example a Taisho Sanke with a red patch on its head becomes a Tancho Sanke. The most sought after examples in Japan are the Tancho Kohaku being an all white fish with a single red spot on the head, resembling the Japanese flag.
Usually abbreviated to just Utsuri, this is a fish with a black base colour with either white (Shiro Utsuri), red (Hi Utsuri) or yellow (Ki Utsuri) markings. Although first developed in the 19th century, it wasn’t until 1925 that the variety was officially recognised. The name of this variety translates as reflection and alludes to the suggestion that colour is reflected on to the black body of these fish.
Often confused with the Utsuri, this variety is actually the exact opposite having a coloured base with black markings or sumi over the top. Bekko, which translates as tortoise shell can have a base colour of white (Shiro Bekko), red (Aka Bekko) or yellow (Ki Bekko)
One of the first varieties to be recognised as far back as 1850, Asagi have a grey-blue colouration above the lateral line, each scale has a dark blue edge which also gives the impression of a net like pattern while red is the dominant colour below the lateral line. Asagi literally translates as pale greenish-blue.
In 1910 Yoshigoro Akiyama crossed an Asagi with a mirror carp, the resulting fish is scale less except for a single line of large mirror scales dorsally, extending from head to tail. Shusui translates as ‘autumn green’.
Literally translating as ‘tea coloured’, Chagoi are a uniform coloured fish ranging from olive green to copper orange. This variety is favoured by koi keepers for its high growth rate and docile, friendly personality which tends to rub off on it pond mates and make them all less skittish. It’s not uncommon for Chagoi to interact with their owners, even taking food from their hand.
There are a few varieties of koi that share a similar solid, metallic coloured base. Matsuba and Ogon are single colour with or without scale edging. Kujaku have patches of red/orange/yellow on top of a solid white base with black scale edging. Hariwake have more prominent colour patches on top of a solid white uniform base.
Kinginrin which is usually abbreviated to Gin Rin, can describe any other colour variety of koi which have sparkly scales. Gin Rin translates to ‘silver scale’ and is a genetic trait first introduced in the early twentieth century from a wild carp discovered with an abnormal glittering scale pattern.
Doitsu-goi, usually abbreviated to just Doitsu refers to a particular scale pattern introduced into koi varieties by cross breeding koi with the European mirror carp (Cyprinus carpio carpio). This creates a scale-less fish along the flanks with usually a single row of enlarged scales along the lateral or dorsal lines. Doitsu is the Japanese word for Germany - the country that first cross bred koi with mirror carp to produce this scale pattern. Most varieties are available as Doitsu and remain the same (e.g. Doitsu Sanke). Doitsu Asagi were given their own breed name - the Shusui.
Ghost koi were created by cross breeding Ogons with common carp in Europe in the late twentieth century. They provided a tougher breed of fish that also grew quicker than domesticated koi. It is believed the 'ghost' refers to the early breeds of ghost koi that were so dark in appearance, only a few of their metallic scales could be seen from above, giving the illusion it was a ghost of a koi!
Butterfly koi are another newer addition to the koi world and have been selectively bred to accentuate the length of their fins. Some true koi keepers do not regard these as true ‘Nishikigoi’ but more of a mutant variety. Nevertheless, these can provide a pond and their owners with something unique and charming in the pond.
Do all koi still come from Japan? Why are they so expensive?
This question is often asked by koi keepers as where the fish originate from can be important. The most expensive koi seen for sale will undoubtably be from Japan, with a registered farm and often their family history available. This puts koi on a par with pedigree breeds of dog (and a cost not too dissimilar!) Many koi auctions in Japan reach headline news for the prices some go for. In October 2018, a koi auction made worldwide headlines for a record sale of a 101cm Kohaku for £1.4 million! A grand champion koi will be highly desired to become breeding stock, so they can pass on their strong genes to the next generation of winners.
Japanese koi are usually only found in the more specialist koi retailers. Israel has become a huge exporter of more affordable koi over the last few decades. Many believe they now compete for variety and colour with their Japanese counterparts. English bred koi are also getting better in variety and quality. Some UK retailers are opting to sell locally bred stock to reduce stress and their carbon footprint.
It is important to ask the fish store where their koi have originated from. Koi from different countries can be carriers for diseases that don’t directly affect them. Crossing fish from different origins can cause a catastrophic disease outbreak.
How long do koi live for?
Browsing the internet, you are bound to find stories of koi that are centuries old. The infamous koi ‘Hanako’ lived to an astonishing age of 226 in Japan. The age was verified by counting the growth rings of Hanako’s scales under a microscope. Much like growth rings of a tree trunk, the growth spurts of summer and the slow winter proved at the time Hanako was 215 years old. However, it would not be expected that every koi will reach this grand old age. A more realistic lifespan for a koi, given the correct water quality, space and healthy diet, is approximately 40 years.
Other species of pond fish for the outdoor pond
Whilst koi are beautiful, friendly creatures, they do come with their own level of specialist care for long term success. If your outdoor space favours a more traditional garden pond, with aquatic plants and attractive to wildlife, there are other varieties of pond fish that are more suitable for the pond. Below we highlight the most popular species available.
Goldfish - (including Shubunkin & Sarasa)
The traditional goldfish (Carassius auratus), native to East Asia but introduced globally, is farmed in their millions and is one of the most popular pet fish kept in the world. They come in a variety of colours - red & yellow, sarasa comets (red and white - elongated fins) and shubunkin (mottled blue & orange - elongated fins). Expect goldfish to grow to 30 centimetres and live for approximately 20 years.
Orfe (Leuciscus idus) are a European native species of shoaling pond fish that make a great addition to a garden pond. Introduced into Britain in the late Nineteenth century, they come in a few different colour morphs (blue & gold) and a natural silvery colour called ide. It is a large growing species, attaining a potential size of up to 60cm. They will therefore require a large pond that is well oxygenated.
Silver or Golden rudd (Scardinius erythrophthalmus) is a medium growing species that is a British native. They can attain a size of approximately 30cm and like to be kept in a group. Rudd are prolific breeders - expect them to quickly populate a garden pond! Rudd possess an upturned mouth so prefer small floating pellets / flakes and may even help keep the midges population down by eating insects that land on the water’s surface.
The fantastically named tench (Tinca tinca) is a British native bottom feeder that is colloquially named the Doctor Fish. Tench secrete excessive amounts of mucous that other fish will ‘steal’ by rubbing against the tench’s sides. Expect tench to grow to around 45cm and are available in natural green and a ‘golden’ variety - which may be easier to see when they’re at the bottom of the pond!
Grass carp (Ctenopharyngodon idella) are native to East Asia and are often bought to control algae in the pond. However, be aware that grass carp can reach 1.5m in length and are easily spooked - always cover the pond to prevent accidental jumpers! Interestingly, grass carp are, by weight, the most commercially produced fish in the world (over 5 million tonnes per year! In Scotland, by comparison, salmon production reached just under 190,000 tonnes in 2017).
Sterlets and sturgeon (Acipencer sp) are a group of primitive fishes that, on first looks, resemble sharks. Whilst they share many characteristics of sharks, they do not in fact share a relatively common ancestor. The fossil record suggests they have evolved from bony fish ancestors. The cartilage skeleton structure must therefore have an evolutionary advantage over ‘true’ bones.
Sterlet and sturgeon are large growing species of bottom feeders. They require pristine water quality and well oxygenated water to thrive and some varieties can exceed 1.5m so do your research but adding one to your pond.
Image reference: Queni Koi, The Northern Koi Club, Velda, Fish laboratory
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