Are Discus Tolerant Of Fertilizers

[silvery37]

I would like to have a planted tank with discus. Will the discus be tolerant of adding phosphates and nitrates. I have heard they are sensitive to nitrates. How would keeping the nitrates at 20ppm do for the fish and the plants?

 

[nry]

They will be fine with EI/Estimative Index dosing, as proved recently by Tom Barr in a massive tank which should be on this forum somewhere. Try hunting out the 'behemoth tank' thread via search I think.

 

[Themuleous]

Yeh, people have been keeping discus in planted tanks that get ferts added for years, no issues at all. Indeed, the benefit of the plants, i.e them 'cleaning' the water and keeping it in tiptop condition is probably why discus look so dam good in planted tanks!

Sam

 

[plantbrain]

I think in the past many assumed that NO3 via KNO3 was = to NO3... via NO2..... via NH4.... via fish waste....... via Fish food.
A few more steps involved and assumptions with some very toxic N based compounds along the way.
N for N, the NH4 exposure alone required to produce 20ppm of NO3 is extreme, and is cause for concern.

However, side stepping all that with a very non toxic end product and plant fertilizer, NO3, works quite well.

The problem was many assumed that NO3 is the issue, not the entire cycle.
All they read is high NO3 are bad, not that the source starts with fish food and leads to these other extremely toxic by products.

When you over feed fish like many Discus owners do, they also use a lot of O2, as does every breakdown step through the N cycle. This produces large amounts of waste.

Generally, Discus folks measure the end products to do water changes etc, not the NH4/NO2 since they are transformants and are somewhat rapidly converted via O2 and bacteria.

However, even small amounts of NH4 being produced take time to get the filter bacteria etc and low levels build up even with a good filter. This places stress on fish.

It also removes O2.

KNO3 does neither.
It drives plant growth, and thereby removes NH4 as the plants grow and remove that as well as add O2.
Overfeeding your fish does neither

Regards,
Tom Barr

 

[silvery37]

Thanks for the great responses. I will be getting some discus

 

[Themuleous]

Very interesting Tom, didn't look at it like that, cheers for sharing

Sam