hi paul, can you, or someone else on the forum help me please. assuming for the moment that my pond filtration and other basics are ok - and the pond as is has run for the last few years - my 16 fish ranging in size from 50cm (true) down to 20cm, will hopefully keep growing/eating/flushing their systems into my water. how and at just what stage do i take steps to prevent the total population coming under threat? all look healthy and fat and all eat like horses. i restrict the food given to one small scoop of pellets once a day and it is consumed immediately . seems like the rest of the day they eat the algae growing on the walls and anything else that falls into the pond. is there some magic formula that says how many fish for how many litres of pond water? and are these formulas believable? i would rather keep less fish if it means longer term stability
- cheers dave

I've Read Its 1 Large Koi To 1000 litres Of Water And I Think 50 cm Qualify For A Large Koi lol But Think Probably Allso Depends On How Good Your Filter System Are If U Wanna Keep More Per 1000 Litre.

From what i understand, the question:

"The amount of waste that a certain filter can handle per hour ?"

is more important than :
"how many fish for how many litres of pond water?"

NB! "Amount of waste that a filter can handle per hour" is different from "Amount of waste that a filter can handle per day"

So, if you feed your koi frequently with small amount of food each time. Provided that your koi is keep on growing bigger. Provided that your filter is matured. And you still get a reading of ammonia of zero, that mean you are still ok.

If you don't get a reading of zero for ammonia than you should either increase your filters or decrease the number of koi in your pond.

The above is only my opinions, maybe is right or maybe it's wrong.

The experts recommend 66,6 cm of fish per 1000 liters.

Dave, you have a 8000 liter pond, and therefore, according to this rule, you may have a total of 532.8 cm of fish.

From your previous post, I gather that you have 16 fish with an average of 35 cm. (35 x 16) That brings you to 560

Obviously your filtration system is relevant. But, just remember, sooner or later something will go wrong with your filtration system. You might have to medicate and loose your beneficial bacteria, you migh have to fix a leak and loose the maturity of the pond, etc. In such a case, the efficiency of your filtration is irrelevant.

If power goes down, the efficiency of your filter is also irrelevant. The fish needs oxygene, and if your are overstocked, you might loose a lot of fish.

You also have to keep room for growth, and remember, the more fish per water mass, the slower they will grow.

Rather give your best fish perfect conditions by selling some of the lower quality fish.