This tank is over thirty yrs old and is biologically very well established. It is 140 gallons, and runs on biofitration balls. I think in all the years I’ve had it, I’ve did a water change maybe two or three times, don’t use store bought chems for anything. What it comes down to is you need to have the proper environment for whatever it is our keep. There are more fish in there than you think, but don’t forget, a one inch fish needs a minimal of ten gallons to flourish. It may not look purty but my fish are heal
