filterless tanks good for fish's health?

[gregorsamsa]

I think its possible to have filterless tank if its well planted lit etc.

However, maybe my bioload very very high. But once i switch off my internal filter, the behaviour of my fishes is that they go higher level and are spreaded out.

In my opinion, ignoring the bioload, i think without water movement from the filter, its a bit unhealthy for the fish firstly because there is no circulation.
And also for fish to be healthy, they need to swim against current, like tin the wild.

What do you guys think?

[budak]

Well, most of us use a filter to provide a high density substrate for biological filtration, allowing waste to be quickly converted to NH4 to NO2 to NO3 (which plants take in). The other purpose is water circulation (quite important in my experience), which a powerhead will also serve nicely. My view is that in a low bioload tank, a powerhead could arguably suffice, but a good filter adds in valuable spare capacity in biofiltration that could buffer any shocks.

But for very small tanks (1 ft or less), if bioload is low, you can do without powerheads or filters altogether, if planting is heavy.

[elmike]

I've seen as many as 10 guppies thriving in small filterless 1 ft tanks with only a bunch of Elodea. It's not impossible, but you might want to select the more hardy fish. Small tanks, small fishes.... like platies, honey gouramis, or bettas. You can do more frequent water changes by scooping and topping up... that was what I used to do with my small tanks.

[mordrake]

bio-filtration aside, i think fishes that are "air-breathers" like betta or guppies would be able to do well in a filterless tank. however, for the other fishes that take in o2 from the water, you'll find them at the surface gasping for air due to low o2 levels in the water. so u might need to have an air stone.

[budak]

Guppies are not airbreathers. Bettas/gouramis/some catfish are.

I don't think the type of fish matters much, as long as the tank is not overcrowded and plants are ample. As I said, a filter provides extra biofiltration capacity that allows you more leeway in NH4/NO2 conversion if you overstock your tank somewhat. My little filterless tank has shrimps, loaches and Boraras which do just fine.

[mordrake]

[quote:08d0142c90="budak"]Guppies are not airbreathers. Bettas/gouramis/some catfish are.

I don't think the type of fish matters much, as long as the tank is not overcrowded and plants are ample. As I said, a filter provides extra biofiltration capacity that allows you more leeway in NH4/NO2 conversion if you overstock your tank somewhat. My little filterless tank has shrimps, loaches and Boraras which do just fine.[/quote:08d0142c90]

hmmm... have been seeing guppies in cube tanks for so long that i thought they are air-breathers

even without a filter, i'm sure the fishes n shrimps wouldn't mind having an airstone in the tank

[elmike]

[quote:c32581149c="mordrake"]... so u might need to have an air stone.[/quote:c32581149c]

That has a disadvantage. An airstone in a filter-less tank would churn up the poop and the debris, and you would have problems with water clarity. That has been my experience. Of course, unless you are not fussy with having crytal clear water.

[mordrake]

[quote:6d36ceda="elmike"][quote:6d36ceda="mordrake"]... so u might need to have an air stone.[/quote:6d36ceda]

That has a disadvantage. An airstone in a filter-less tank would churn up the poop and the debris, and you would have problems with water clarity. That has been my experience. Of course, unless you are not fussy with having crytal clear water.[/quote:6d36ceda]

mike, set it to a gentle stream of bubbles la

[gregorsamsa]

i use to have a 1 feet tank with some danios without any water movement. Compared to now, my danios seem healthier.

My feel is that a tank without filter and water movement is possible but it is like imagine you are in the Forest and the Air is heavy because no wind.

[juggler]

In ponds, there's not much water movement too, right? Except when the wind blows across the surface. Or else there may be convection currents in the water as it gets heated under the sun.

So can take it that your filterless tank is like a stagnant pond.

Like what Budak said, if you don't overstock the tank and have sufficient plants to serve as waste (ammonia etc.) removal, it should be fine.

[budak]

On things like airstones, I must I say I dislike their effect (whether fine or big bubbles). Anyway, if a tank can thrive without something (filter, airstone, etc), as many small, lightly-stocked tanks are doing, why bother with the extra trouble?

[elmike]

I don't understand what gregorsamsa is saying... about his situation? but I agree low fish load is the way to go with small filter-less tanks. My choice is a pair of platies - a boy and a girl

[elmike]

Something on ponds...

The next time you visit the Singapore Zoo, take a peep into the mini ponds there. You will see some with congested population of giant gouramis hanging at the surface gasping for air particularly on a still hot day. So ponds without good circulation can be short in oxygen level if there is overcrowding.

[juggler]

[quote:7e01e3e29d="elmike"]Something on ponds...

The next time you visit the Singapore Zoo, take a peep into the mini ponds there. You will see some with congested population of giant gouramis hanging at the surface gasping for air particularly on a still hot day. So ponds without good circulation can be short in oxygen level if there is overcrowding.[/quote:7e01e3e29d]

Mike: If I remember correctly, those zoo ponds do not have aquatic plants. If they do, they may have helped in the filtration and oxygen supply. But I think there's not point putting plants in there since the Giant Gourami eat plants.

[gregorsamsa]

haha. i think my post has been misconstrued. What i meant to say is whether in any water body having fish, is the lack of water current detrimental to the fish's health?

For example, maybe because of lack of current, the fish might suffe from muscular dystrohphy etc

[elmike]

[quote:5f045e8aed="gregorsamsa"]For example, maybe because of lack of current, the fish might suffe from muscular dystrohphy etc[/quote:5f045e8aed]

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