I never use filters on my tanks, just power heads for circulation. They're all set up as Walstad tanks -potting soil capped with gravel, lots of plants. I just tore down the first one - a 10 gallon that had been running for 3 years just fine. My largest is a 50 gallon with 5 Pearl Gouramis, 13 Rummynose Tetras, 3 adult Bolivian rams. Nitrates stay between 5-10 with only occasional partial water changes.
Life isn't stone, it's water.
PSA: When talking about baby fish, "fry" is plural.
I have a fry. I have some fry.