Does Heavy Fish Stocking Help Plant Growth

[fry_lover]

i heard about Diana Walstad but not read much, does she include some techniques or advice on plant growth and heavy fish stocking (as mentioned to me on a different forum)

I have a very heavily stocked 48x24x18 which holds about 330 litres (90 US Gallons), its fully of cummunity fish such as livebearers and tetras. Its well above "normal stocking levels" and has been this way for a while. I am getting really good plant growth despite no added co2 and living in a hard water area.

My WPG (US) is about 2.0 and (UK) is about 2.4

My plants are "easier" ones but they are looking real good.

Are they getting quite a lot of needed nutrients from the over-stocking?

My tank readings of nitrate are lower than my tap-water even if no water change in 14-17 days and i dont really have any algae in there, only if i put one of the bulbs (there are x4 40W) too close to the front, then some of the front glass with algae

Tap-Water approx 15-30 mg/l Nitrate (varies)

Tank has been as low as 5mg/l Nitrate, but normally is 10-20 mg/l, mostly closer to 10mg than 20mg

 

[SuperColey1]

Another age old question with many answers really.

In short the answer is Yes the fish waste is a good source of nutrient and also the fish food (because they never eat everything)

Now comes the variables boring bit.

Dependent on your water change frequency and amount then you are removing some of the nutrient from the tank hence why Diana's ideas are aimed at not using filters and not changing the water. The plants are her filter.

She also uses soils as her substrate and this will of course also contain nutrient which will work alongside the nutrient from the fish waste.

Andy

 

[fry_lover]

Another age old question with many answers really.

In short the answer is Yes the fish waste is a good source of nutrient and also the fish food (because they never eat everything)

Now comes the variables boring bit.

Dependent on your water change frequency and amount then you are removing some of the nutrient from the tank hence why Diana's ideas are aimed at not using filters and not changing the water. The plants are her filter.

She also uses soils as her substrate and this will of course also contain nutrient which will work alongside the nutrient from the fish waste.

Andy

thanks for feedback, well the "plants as filters" certainly is true in my tank, i actually didnt realise (inch) wise how over stocked it is, as all the fish are pretty small and lots are Cory's and Khuli Loach and the tank is 48x24(high)x18, but i never have ammonia or nitrite readings and the nitrate is normally less than my tapwater as mentioned, even after no water change for a while.

I usually do small water changes of 15-20% every 4-7 days, what do you think? All fish doing well, nice colours, no probs, tank looks nice, will post pics later, been this way for a while

Substrate is sand and i do use Seachem Flourish (but less than the recommended dose)

 

[SuperColey1]

If you have quite a few plants the try not doing any water changes for a while and just check the ammonia, nitrite and nitrate readings.

If the readings start to show some then do water changes.

I would assume that eventually there would be no need for water changes at all!!

Andy