As per request by @Pascal... (and @TofuHaroto, @Deli, @zeusthemoose) here's a little information about my smol pond.
I said in my post it was a Koi Pond but currently it's more of a Goldfish Pond with Koi.
It's about 3 dozen Goldfish and only 4 Koi, but the longterm goal is to get rid of most of the goldfish (sell or giveaway, not flush the toilet ofc lol) and replace them by a couple more Koi.
In the end I want only 7-10 Koi total. But before I get there I first have to rework the filtration system. Currently it's being filtered through a sieve that takes out a big portion of leaves, shit and whatever, and after goes through a Oase 36000 sponge filter, all pumped by a Oase Aquamax Premium 10000 with attached Skimmer. The pond itself is about 10y/o now and contains only 7000 Liters with ~1.4m max depth and is very true to nature, as you can see by the many many plants it's surrounded by in the summer (which leads to a metric f-ton of organic waste sadly).
Because of the many fish and therefore food, the pond isn't always as clear as I want it to be which is why I want to redo the filtration system and have it crystal clear at all times. Stuff really is expensive though so I'm looking to snack some deals rn, like the 27000l/h pump I showed.
All in all it's not perfect by any means but I love it and after all the daily work you have to do on it, it's a real oasis to relax and chill.