Also highly recommended to anyone who wants to nerd out on ecology: Rachel Carson's Silent Spring https://www.fadedpage.com/showbook.php?pid=20151002 , which among other things lead to the ban on DDT in agriculture in the US. Still relevant, and beautifully written.

Any guides on what kind of equipment and set up is needed to get started? I've been having thoughts of having a "slice of nature" like you said. But I don't know what's the way to get as close to a self-sufficient and passive system as possible.

Theres a great forum called ukaps (https://www.ukaps.org/) which has tons of resources for getting started. Its a highly addictive hobby! Also recommend watching some of the cinescaper videos on youtube for inspiration :)

I think you can get pretty far by searching on YouTube for “walstad method tank” or “walstad planted aquarium”.

Some people start with a large jar, while others try something like a 5–10 gallon tank. You can go very small to start.

In a tank system, it’s helpful to include either a small filter or power head to maintain water movement. If you’re adding a lot of plants, a head is sufficient because the plants and animals will do a great job of filtration. I use snails (naturally occurring) and shrimp (purchased, but I’d like to find a native equivalent) to aid with cleanup, and the water is crystal clear after several months with no water changes, only top ups to account for evaporation.

If you want to include animals like fish, you really should ensure you do some research first and establish something with a lot of plant life. The fish won’t thrive without a suitable habitat and usually, most species require some water movement and excellent filtration.

As for self sufficiency, the systems will run on their own for extended periods quite well, but if you add more fish for example, you’ll generally need to add more food. Even so, this can be a very occasional event. With mine I will add material I find from my worm composter such as small white worms which colonized on their own. I’ve also experimented with raising daphnia in a jar with baker’s yeast as their food. I think I’ve only added external food once per month or so, and I’m not sure this was actually necessary. The system produces a huge amount of micro fauna and algae which the animals go crazy for. The animals are all tiny, too, so their feeding requirements would naturally be far less than your typical fish tank system.

The book is also a great guide, though it’s a little advanced. It assumes you know a bit about the hobby of aquaria, both planted and with fish.

In any case, I’d say it’s easier than you think. With the right understanding, it’s hard to fail. It’s incredibly complex, but establishing a good culture and allowing it to thrive will generally ensure it remains well balanced with very little intervention.

Get a 20 gallon tank with grow light hood, add dirt (organic potting soil), cover with aquarium rocks, add aquarium plants, 6-12 shrimp, and 4+ snails, add a sponge filter, enjoy your little ecosystem.

This is pretty much it! The book promotes sand over aquarium rocks (ideally living sand from a lake, pond, or river bank, laws permitting), but I’ve seen people have success with fine gravel/coarse sand as well. If it goes in ‘dead’, it’ll be live within a month for sure.