can fish tank filters be replaced by water changes or is the filter a must?

An experienced fish keeper can use plants and water changes but that would be a very experienced fish keeper.

So yes a filter is a must .

Technically yes, but it's not really practical, like 50% water changes every day???

MUCH simpler and easier to just get even a basic filter. Even an air powered sponge filter (about as cheap as it gets) will provide good biological filtering. Heck you can even make a filter out of a plastic soda bottle, some nylon wool, and a plain gravel. Wont be a Great filter, but cheap and better than nothing.

Otherwise there is the Walstad method, where the tank is filtered by plants. But this is more technical, needs the correct substrate and lighting. So it's costs more than just buying a cheap filter.

Ian

Ian

filters are a must. reguardless with a filter you still need to do water changes and maintain the filter and clean it as well as changing it.

filters provide water movement for the tank which basically puts air into your tank which is a must for everything no air supply = death. some fishes can gulp air from the surface but this is VERY unattractive and the noise can get very annoying as well. and im sure it stresses the fish out when they try to sleep constantly swimming up to breath.

the filter also cleans your water as well with the chemicals etc.. but the water changes are still needed

Without a filter, you would find yourself doing constant water changes to keep your fish healthy. Most people will get tired of this. So I would say yes, a filter is necessary.

I just did a little project. 1 gallon with no filter. Took me 3 weeks to get the water values stable but now I'f got the light sorted it's ticking along nicely. Of course it's 85% planted.

you'll see that most informed answers will say that "technically yes"

but then they'll try to say something to indicate why you wouldn't do it.

if you research all about the chemistry of fish keeping and the ratio of waste to waste reduction potential

as it relates to the exact tank and fish you wish to keep,

then yes, it's possible.

but usually that's not what someone means, what they are saying is often:

"I don't want to spend money or understand anything, I just want fish in a bowl"

filters pull out constant waste, water changes pull out a big percent ,of ammonia,nitrates,nitrites.so no you do need a filter still

yes! However some fish can live without them like the Eel (Anguilla rostrata) as long as extremes are avoided(high ammonia)