Is it even possible to have a tank with no filtration?

[TwoTankAmin]

esoxlucius
esoxlucius

I'm confused. You state "100%" that "no" you can't run a tank with no filter. I read that as, if you want to run a tank properly you need a filter?

No, the title of this thread is not the question: "Is is even possible to have a tank with no filter?"
It is the question "Is it even possible to have a tank with no filtration?"

My reply answers the question that was asked. A filter does not do filtration, the media inside the filter does not do the filtration, the bacteria which colonize the media in the filter do the filtration. However, those bacteria do not need a filter to colonize and function. Plants are filtration, bacteria in the substrate and on the plants as well as on other hard surfaces in a tank are the filtration.

A filter is a mechanical device which holds media and pumps water through it. To some extent this also creates surface agitation to promote gas exchange and provides some current to move water in the tank. As long as one has oxygenation and sufficient circulation, the filter is not needed. Usually the proper size filter for a tank will provide adequate agitation. However, the tank may still need a pump or power head to improve circulation.

Biofilms are communities of microorganisms (see below) in which cells are embedded in a self-produced matrix of extracellular polymeric substance (EPS), which is often called “slime”. The cells adhere to each other and/or the surface. Biofilms are a system/network of microorganisms that adapts to environmental conditions. They form on living or non-living surfaces and are prevalent in natural and artificial settings. EPS is a polymeric conglomeration generally composed of extracellular biopolymers in various structural forms. Biofilms are the basis of substrate-bound aquarium biofiltration.

from http://www.swisstropicals.com/library/aquarium-biofiltration/

 

[CichlidBeautyAlways]

I've often wondered if this could be done realistically or only for certain tank sizes/applications. So in theory if you had a large enough tank with light stocking, could it work?

it makes u question bc them iving in the wild but i read that the plants in the wild make up for the oxygen...dont run w that bc theres so much that isnt true online....very good question

 

[FINWIN]

We may be getting into semantics here, so it might be good to clarify the question.
FINWIN do you mean, run a tank without a designated filter? Or??????
And by this I mean anything added or designated to induce filtration, anything from under gravel filtration, HOB, internal box filtration, canister, sump, protein skimming, fluidized bed or ???? etc etc etc
Or without any artificial means of filtration? Some filtration is going to occur whether planned or not.
As some stated, biological filtration is always occurring in any cycled tank whether or not there is a designated filter attached.
And water movement is actually not the same as filtration, although water movement does enhance naturally occurring filtration in a tank.
So as you can see, there are differing concepts as to what is meant by, or considered filtration, by different people.
I took your question to be,, without some type of designated contraction that acts as a filter.
But maybe I didn't get the drift?

No you got it right...say a tank with substrate, fish, water and plants. Nothing else.

 

[duanes]

When you compare natural systems, where there is @ 1000 times more plant biomass ratio compared to animal biomass ratio, you see the problem most aquarists face.
Does a heavily planted 30 gal tank with 1 neon, come even remotely close to that 1000 to ratio? And/or is it a desirable tank?
And then compare that to a 100 gal tank with 1 semi adult oscar, its even more of a biomass miss match, even with the help of man induced filtration.
Then factor in that most natural systems are not static, changing seasonally from month to month, sometimes week to week.

Above a small system on the island where I live, during the dry season
its maybe a few hundred gallons, whereas in the rainy season a couple thousand.
For whatever reason it does not support fish life (as far as I have seen)
At times it is filled with tadpoles, but they leave, and at other times large population of shrimp live there.
Predatores such a birds, turtles and other reptiles constantly alter the animal biomass population in the system.
You can easily see the comparatively large amounts of terrestrial vegetation that use up nutrients the animals excrete
Below the same system a little down stream during theft season.

 

[FINWIN]

Makes sense...probably impossible to mimic the oxygen, photosynthesis and water movement in a live eco system. Not without renting a public aquarium, lol.

 

[Nilsafeller]

My 75 gal grammodes tank has no mechanical filtration... just circulation and plants... plants and bb do all the work... I think a heavily stocked tank needs some kind of mechanical and depending on types of live stock in the tank like for my 210... the geos make such a mess of the substrate moving waste around the tank I need sponges to collect debris... tank also gets somewhat heavy feeding with all the fish in there... but sumps, hobs,canisters... I dont think all tanks need them... do your water changes.. keep water circulates... plants always help ten fold.

 

[duanes]

... but sumps, hobs,canisters... I dont think all tanks need them... do your water changes.. keep water circulates... plants always help ten fold.

I agree, the thing is, most people over stock (whether they believe it or not), so something to bolster, at least the ammonia elimination is minimally required, along with frequent water changes to dilute nitrate.
To me, 2 oscars in a 150 gallon is overstocked if it comes to any sort of attempt at a natural type concept.

And at no time in this discussion have we even considered territoriality, which is a major cencern in any tank of cichlids, or other such fish.

 

[dan518]

Yes you can run a tank with no filtration as long as you have water movement. Bacteria will grow on all surfaces in the tank, like the gravel, glass, any decor in it. So a well scaped tank with gravel and lots of decor will be able cope with a certain amount of live stock just not as much as with a filter. I kept 4 x 6inch fish in a 200 gal for a few weeks with only a power head running and all parameters were spot on.

 

[lp85253]

I've often wondered if this could be done realistically or only for certain tank sizes/applications. So in theory if you had a large enough tank with light stocking, could it work?

sure it is .. the recipe is a lot of water volume compared to stock , decent flow , and plants (usually lots).. plus water changes of course...