# Decomposing plant leaves bad for fish?



## ThatGuyWithTheFish (Apr 29, 2012)

Well, it depends. 

People use leaves to scatter the bottom of their tanks to create a blackwater, leaf litter environment. The leaves can be very beneficial to natural filtration and cycling, as well as releasing good nutrients. I think most people use dead, dried leaves for that. 

However, decomposing plant matter will always release nitrates. Check that first. That's the only real problem it would create, other than being an eyesore. You should use tweexers to remove them.


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## Mxx (Dec 29, 2010)

Nitrates are low, as are other water parameters I've tested which are fine. I thought there wouldn't be any harm in doing so, but I thought I'd check if that could be part of the cause of my unfortunate casualties...


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## HD Blazingwolf (May 12, 2011)

Decomposing matter directly affects oxygen levels. The leaves alone wont do it unless its like when u rake ur yard....
Make sure u have good flow and surface agitation. And a decently clean filter and ull probably be fine


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## Ptyochromis (Mar 16, 2012)

In moderation it shouldn't be an issue. Consider adding a pre-filter to your filter to preserve the impeller, just wrap some filter pad around the intake and change it once the flow starts to go down. 100 times easier than tearing your filter apart and will help prevent BGA.


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## Mxx (Dec 29, 2010)

The fundamental question perhaps is, do low oxygen levels help pathogenic Myobacteria to flourish?

No problem with the impeller or blue-green algae. 

The canister filter is over-sized for this tank though, by a factor of about... 10 or 15, as it's a fluval 305. The hope is that it would readily mineralize any organics in the water, and as a byproduct would be pumping out a steady supply of CO2 as well. 

That was the idea anyway, but perhaps something is out of balance there, or perhaps it's just some other type of disease which has nothing to do with the lights/plants/filtration.

However, my tank is low-light so maybe the plants aren't even producing a sufficient amount of oxygen. And as the fluval edge has restricted surface area, that obviously doesn't help either. 

With all the talk of covering up tanks tightly to reduce co2 off-gassing I wasn't too worried about my oxygen levels initially. And when I tested the levels, I did have high oxygen levels or low oxygen levels, possibly something in-between. To tell you the truth the bloody test kit's results were useless and impossible to read...


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## HD Blazingwolf (May 12, 2011)

Plants really dont create much oxygen. Covering ur tank will not reduce c02 loss unless its very well sealed and pressure can build inside


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## Ptyochromis (Mar 16, 2012)

If you cannot reach the organic buildup, try agitating your tank with a baster, hose or just waving your hand around to lift the bits into the water column where you can siphon them out, and what you cannot get your filter will pick up. Then you can clean your filter to remove the rest (or just replace the prefilter).

Make sure you have good surface movement, for crucial gas exchange. Also, try and keep your tank no higher than 25c, the cooler the tank, the more O2 will be available to your fish.

There is nothing wrong with over-filtering a tank. I am for 8-10x tank volume turnover per hour.


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