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It was around the early naughties when it became apparent to UK hobbyists that home grown jumbo koi were a possibility. With the sum of money required to purchase quality jumbo go-sanke outright being cost prohibitive to most, growing them from smaller sizes made for a tantalising prospect. 

​I remember at the time magazine’s were featuring more and more articles and forums were flooded with debate on the topic of growing jumbo koi. Hobbyists were building 'grow on' systems in garages and sheds, bakki showers were in vogue and reverse osmosis was being talked about. It was clear that trying to match the growth rates achieved in Japan was becoming very popular indeed and even more so - the dream of 'growing a champion.' It's easy to understand why, it's the 'rags to riches' story that we all love and this new angle on rearing koi made it seem so very possible. 

However, I do think there was a strange sort of confusion caused - the illusion that anyone could do it. This misunderstanding is not the fault of those who brought the information to the masses, but rather the interpretation, hype and Chinese-whispers that happened thereafter. 


Just because it can be done, doesn't mean it's that simple. 

It’s safe to say that the trend of attempting to grow jumbo go-sanke has stuck around and some wonderful things have come from years of such endeavours. It's developed our ideas on filtration, flow rates, feeding regimes and water management and although as a whole we have sobered up somewhat since the naughties, I do think a reality check is never a bad thing.    

What are the odds?

I think we can all agree that finding true high quality koi with a future, real tategoi, is not the easiest of tasks. Couple this with a koi that has the potential to grow jumbo and your chances become even more slight. Quality jumbo go-sanke occupy a minute percentage of all the koi produced. Make no mistake, if you ever find yourself gazing upon a 85+cm go-sanke, take a moment to contemplate the chances of a tiny fry achieving such a formidable size and possessing such outstanding quality. Consider the risks and work involved. Then you will realise how special and rare that koi before you, truly is.


We take such things for granted.   

The Checklist - What to look for:

Bloodline/Body Shape.

The former, a history lesson on heritage to inform us if the koi has the genetic potential to reach such a size, the latter a physical indication of the koi’s structural strengths and weaknesses. 



Will the koi actually posses any quality when it reaches jumbo status.  


Everyone wants a great pattern but in the search of potential jumbo koi, pattern comes last. Why? Because if you have the body and the skin AND the pattern - the price will be EYE-WATERING to most of us in the UK. Pattern plays a big part in the pricing of any koi but with a little imagination a koi with a less desirable pattern now, might become more desirable later, as the sheer size and quality of the koi in question become the overriding attributes.

Finding such a koi sounds easy doesn't it?

Well it isn't, mainly because there's no one that can truly predict with certainty if a koi will grow jumbo. Those stating that they can, are probably fibbing and those salesman shouting such things as - ‘will reach 85cm’ - ‘future jumbo koi,’ are somewhat using sales patter over actual fact. There are far too many variables to take into consideration to give such a certain appraisal, hence why the breeders themselves tiptoe around such questions. 


...Think About It This Way

If anyone could predict with absolute certainty which koi would make quality jumbo specimens, it would be the breeders themselves. In possession of such knowledge they would select out this minute number of highly valuable koi at tosai (and it would be minute). They would then leave them well alone in their best systems, rear them for some years until jumbo sizes were achieved, enter them into koi shows and the rest would be history. Easy. 


But this is not reality.


The reality is that the breeders don't possess such a knowledge and things aren't so black and white. So they must select a number of tategoi at each stage of the rearing process based on certain indicators that those koi MAY become good. The likelihood of which reveals itself, bit by bit, year by year, after each harvest and after each gamble the breeder takes. Think of the volume of koi that don't make the grade... Only a tiny number of tategoi may ever obtain true jumbo sizes, if any at all! Please note the breeder also understands the value and importance of true quality koi at any size. Some breeders simply don't produce jumbo koi - it's not all about the big girls you know! 

One needs to understand that finding such a koi is no easy feat in itself, the odds are stacked against us and if we do find one with the right potential, they don't usually come cheap. 'Define cheap' I hear you ask...well take a look at any dealer who stocks such a koi and decide for yourself. Then consider the risks and costs involved with rearing it and then remember that for every koi that makes it, thousands don't! You must be happy to roll the dice and most importantly don't forget...


There are no guarantees. 


You must have the correct pond, the correct knowledge, the correct koi, the correct rearing regime and even then, it's still a gamble and as they say - don't gamble if you can't afford to lose!

For every koi that makes it, thousands don't!

Back to life, back to reality.

I don’t say all this to be disheartening or to dissuade anyone, but rather to highlight the reality, the odds and the risks involved in chasing such a dream. I see many hobbyists who, for some reason, seem to think that growing jumbo go-sanke is easily achievable. Their journey is destined to be an expensive and frustrating one. Why? Because most of us don’t posses the necessary resources to purchase and rear such specimens.

And that's ok!

It's much better to be honest with ourselves about what our system, knowledge and wallet are capable of. That way we can either start from scratch, fine tune or find better suited dreams to pursue! For those hobbyists that do attempt to grow jumbo go-sanke and do so seriously, it makes the possibility of owning such specimens more achievable but only those hobbyists will know the true cost of pursuing such a dream...


I think we can all agree there is nothing more spectacular than a quality jumbo nishikigoi and I have nothing but admiration for those hobbyists who bring them along to our koi shows for our appreciation. But the reality is that for the majority of us our efforts would be better focussed elsewhere. So...

What are your koi keeping dreams?

Seriously, think about it...maybe you reevaluate the hobby, maybe you decide to build a more suitable pond, maybe you rethink your purchasing criteria. Either way I think it's worthy of some pondering.

Identifying what you want from the hobby before you start digging is the cheapest way to build a koi pond. It doesn't always work out that way, but for those of you who haven't started your build, see my article:

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