Is it okay if I don't do water changes?

I'm going to be honest, I haven't done a water change in any of my tanks for 2 months now. I only change it when the water level gets too low, and even then I've just been putting in more top water and vacuuming for a few seconds. I test the parameters every month, and they're always the exact same as last time. The TDS doesn't change either. No Nitrates, ammonia, or nitrites for about seven months now, and I've been doing my tanks like this ever since I got them a year ago. Can I go on like this? What happens if I don't do water changes?

 

I would probably still change the water at least once a month, but thats just me. I know my tanks can go almost a month without a change no problem, but that doesn't stop me from doing it weekly. But i also may stock a lot more heavily than you do, too.

 

Do you have a bunch of live plants? As far as I know, your nitrates shouldn't be at 0 with no water changes unless you have a ridiculously planted tank. The problem with not doing water changes is the nitrates build up and eventually the tank could crash. How often you need to change the water depends on stocking and tank size. I would be cautious and change the water at least every month like BigManAquatics said, but I don't know enough about your tank to really know what'll happen. Good luck with your tank though!

 

In short: There are setups that can go for months without waterchanges.
There are also setups that can go for years without waterchanges.
But the vast majority of setups can only go a few weeks without waterchanges.

It all depends on several different factors: Plant density, stocking density, filtration, parameters of the source water, substrate, decorations...

So without knowing something about your tanks there is no answer even possible.

 

If I don't do weekly/biweekly water changes, the water can get an off odor. I also have found water changes help with algae.
Its a must for me.

 

Do you have a bunch of live plants? As far as I know, your nitrates shouldn't be at 0 with no water changes unless you have a ridiculously planted tank. The problem with not doing water changes is the nitrates build up and eventually the tank could crash. How often you need to change the water depends on stocking and tank size. I would be cautious and change the water at least every month like BigManAquatics said, but I don't know enough about your tank to really know what'll happen. Good luck with your tank though!

My tanks all have at least half of the water column taken up by plants and floating plants. My 10-gallon is pretty much only stocked with water lettuce from top to bottom. I've never had any nitrates in the past year, and I don't even dose ammonia removers. Only a few fish and snails in most of them.

 

The amount of plants you have definitely helps. If you have very few fish/small fish that don't produce a lot of waste you won't see too much ammonia, nitrites, or nitrates.

 

Having a tank that self regulates is definitely a thing. My large tank never goes over 10 nitrates but I still change the water once a month or so. If your parameters stay solid I wouldn’t say you necessarily NEED to do a water change, but just from personal experience my fish love water change day, they always get excited when new water comes.

 

It depends.
A tank with nothing but water, fish, and nonliving decorations will do very poorly without water changes. A heavily planted tank with some shrimp and no fish can do just fine with just top-offs.

If you have a very low-stocked planted tank, it should be fine. If it's planted but with multiple fish, consider a small water change (like 15%) once every week or two. If it's a plant-free tank, weekly water changes are necessary for the tank's long-term health.

 

The main thing that happens if you don't do regular water change happens when you finally have to do one for what ever reason. By then the parameters of the tank water and tap water are so different the fish have been known to die.

Plants are removing nitrates but we do water change for reason other than just reducing nitrates. There are other things we don't normally test for that gradually build up. As they gradually increase the fish get used to it. In this case if you add new fish they often don't survive. My tanks are heavily stocked and lightly planted so get weekly water changes. A lightly stocked heavily planted tank can go longer between water changes.

I am a firm believer in keeping the water fresh and clean for fish.

 

My tanks all have at least half of the water column taken up by plants and floating plants. My 10-gallon is pretty much only stocked with water lettuce from top to bottom. I've never had any nitrates in the past year, and I don't even dose ammonia removers. Only a few fish and snails in most of them.

I find it interesting that you have brought up TDS tests and Ammonia removers. Not common amount 7 month old tanks