What Mrecheese said, but it gets much easier with size.
I have a 4ft x 2ft x 2ft tank with a goldfish (technically my son's) - no filter, no bubbler, minimal water changes. "Palaudarium", so half filled with water, half with air, and planted "islands" in the middle.
The secret - animal stocking rate low per unit area, and plants. So much plant-y goodness no nitrogen compounds are ever detectable with consumer test gear.
I was inspired by this book - https://cloudflare-ipfs.com/ipfs/bafykbzacebjomvunv5gfpbctqd2g7jdczatgsdanlslqgsbtdlcsbrum3o64o?filename=Diana%20L.%20Walstad%20-%20Ecology%20of%20the%20Planted%20Aquarium_%20A%20Practical%20Manual%20and%20Scientific%20Treatise%20for%20the%20Home%20Aquarist%20-Echinodorus%20Publishing%20%281999%29.pdf
Even a 2ft x 2ft x 1ft tank can be very stable as long as it is away from direct sunlight. Don't start with a fish, and certainly not shrimp, but ramshorn snails are pretty sturdy, and will clean the algae off the walls for you.
