Who Gives A Fish Forums

I've been keeping a 20 gallon planted tank for about a year now, and I've been doing weekly water changes. But I've heard some folks say they barely change their water and their tanks are fine. Is it really necessary to do it so often?

It depends on your setup, mate. If you've got a heavy bioload or sensitive fish like Discus, you're gonna wanna stick with regular changes. My 55 gallon with Oscars gets a 25% change every week, no exceptions. But a lightly stocked tank with tons of plants? Maybe you can stretch it.

Water changes aren't just about removing waste. They replenish minerals and stabilize pH. If you're using RO water or have soft water, skipping changes can mess with your params. Test your water regularly if you're thinking of cutting back.

I've got a 10 gallon with just a Betta and some shrimp. I do a 10% change every two weeks, and it's been thriving. Plants help a ton with keeping things stable. Maybe try reducing gradually and see how your tank reacts?

nah bruh, u gotta change dat water. fish ain't gonna tell u when it's bad till it's too late. my cichlids would riot if i skipped a week.

It's not just about the fish. Plants need fresh water too. If you're dosing fertilizers, buildup can cause algae outbreaks. I learned that the hard way in my high-tech tank.

Thanks for the input, everyone. I'll keep an eye on my params and maybe experiment with smaller changes to see how it goes.

mounta7 wrote: ↑Thu Jun 19, 2025 12:10 pm Thanks for the input, everyone. I'll keep an eye on my params and maybe experiment with smaller changes to see how it goes.

Smart move. Just don't go cold turkey. Fish can be chill until they're not.

I skipped changes for a month in my 40 gallon community tank, thinking the plants would handle it. Ended up with a nasty case of cyanobacteria. Now I'm back to weekly changes, no questions asked.

It's all about balance. If you've got a good filter and low stock, you can probably get away with less. But if you're pushing the limits, better safe than sorry.