How Many Fish Can I Keep In My Pond? – LMP Pond Academy

Everyone has their own ideas about how many fish you can happily keep in any given amount of water.

In this Pond Academy video, our Aquaculture Specialist Scott Tucker shares his two cents and gives some suggestions for how to increase the amount of fish you can keep.


How Many Fish Can I Keep?

G’day this is Scotty Tucker,

Just here to give a very brief sort of general guideline for how many fish you should have in your pond.

What most people do with their pond is overload it, and they put in way too many fish.

That then causes problems in either fish stunted growth, fish kills, not being able to survive, dirty water, stinky water, algae ridden water.

You’ve got to feed your fish too much when there’s too many fish in there which means that there’s too much nutrient going in through the fish food.

So you want to try to prevent all this from happening.

So without getting into online arguments with every fish bot and boffin in the world, I’m just gonna share my experience, and what I’ve learnt over the years as a general guideline.

When we’re talking ponds in backyards in Australia, you’re generally speaking Koi or Goldfish.

Koi are the big large Japanese carp, that grow quite sizeable. They’re quite dirty fish in terms of the amount of waste they excrete and their feeding behaviour.

So you’d have a bit fewer Koi in the same size pond than relative to say Goldfish or even native fish.

General rule of thumb that I’ve always worked with is about for every one thousand (1,000) litres of water, one Koi.

If you’ve got Goldfish, maybe for every three to four hundred (300-400) litres of water one Goldfish.

And if you’ve got native fish, similar to Goldfish, you can possibly have a few more natives.

So again, without spiking an online feud with every single fish geek in the known universe, that’s just a general guideline.

There are obviously exceptions to that, and there are reasons when you can have more fish in there and when you should also have fewer fish in there.

How Can I Keep More Fish?

Generally speaking, the more fish you have, or if you don’t remove fish from your system after they’ve bred over the years, or if you don’t remove some of the fish out of your system after they’ve grown after a few years, if you want to house more fish, there are two things that you can do.

One is make sure that you’ve got a very good, working, efficient biological filter.

Because if you’ve got a good biological filter, and if you want lots and lots of fish, make sure your bio filter increases in its capacity as well, that means that you’re gonna break down the waste that fish are producing, that they would otherwise poison themselves by living in their own putrid water.

So putting in a good, sizable biological filter will enable you to carry more fish within the pond.

The other thing that will enable you to carry more fish is aeration.

If you get more oxygen into the water, your fish are gonna thrive, your fish are gonna do better, but most importantly, the bacteria that’s ultimately breaking down that waste and keeping them alive, is going to be functioning more efficiently and more effectively.

And because it loves oxygen, so you’re gonna get the ability to put more fish in or to enable yourself to allow the fish to grow and breed without having to take some out and give them to your neighbours or your mates or whoever.

So they’re your general rules of thumb for your fish, but the main thing is, if you look after your fish with biological filtration and aeration, you’re not going to have many problems and you’re going to have some happy fish for many years to come.


A great, expandable biological filtration system is the Biosteps 10. These filters can be linked together to accommodate larger systems and, like all our biological filters, are super easy to clean.

If you’d like to have a chat about fish or any other pond related queries. head over to our Contact page and submit an enquiry.
Special Thanks to Villa Verde for letting us film in their gorgeous garden!