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fish wastes provide all macro + micro?

16K views 26 replies 14 participants last post by  Robert Hudson 
#1 ·
This is more of a theoretical question, i know there are many other factors to consider like overstocking etc.

But will fish (fed one of the stable diet) waste contain all the necessary components of macro (NPK) and micro (all the trace elements)? So in theory that alone could feritize the plants.
 
#2 ·
Christel Kasselmann says just that in her book Planted Aquariums - Creation And Maintenance (English edition), pages 102-105:

How you feed the fish directly correlates with the availability of plant nutrients. If you feed the fish regularly, the breakdown and digestive products from the fish serve as nutrients for the plants. If, additionally, you provide a nutrient rich substrate, fertilization is rarely necessary. Many aquarium owners fertilize too frequently and too much, which promotes algae growth. Avoid excessive and unrestrained fertilization!

Depending on their species, plants will absorb different amounts and types of nutrients. There are many scientific studies about plant nutrition of terrestrial plants, but only a few reliable scientific results are available on aquatic plants.

In my opinion it is best to fertilize only when the plants show a visible nutrient deficiency, for example reduced growth, formation of chlorotic leaves (bulging veins and yellowing of leaf tissue), or lack of chlorophyll in new leaves or shoots of green-leafed plants (usually iron deficiency). Experiments of mine showed that several of the usually available iron supplements caused the leaves of Anubias to roll up and triggered increased growth of beard and brush algae. Handle iron supplementation with restraint and caution.

If you only want to fertilize specific plants or a small group, use a substrate fertilizer. Dried clay balls of about 1 cm (0.4 in) in diameter, which can either be purchased or homemade (see page 23), work well. Only use liquid fertilizers if overall growth is reduced and you want to encourage all plants to grow faster. A fertilizer made by Danish aquatic plant nursery Tropica called "Mager [sic] Grow" can be highly recommended not only because of its optimal nutrition composition but also because it clearly lists all the ingredients. It would be desirable for other manufacturers to do the same to allow for better dosing when adding nutrients to the water.

Ultimately, all fertilizers must be used sparingly. The dosages suggested by the manufacturers may be too high and should only be used as a guideline since the number of fish and plants vary for each aquarium. Use small amounts of fertilizer at first and observe the results. You can always add more, if necessary.
Some people have said that they agree with this but only in accordance with low light, low tech, and/or low maintenance tanks.

Then of course there's Tom Barr who says

plantbrain said:
They are still wrong about excess fertilizers such as NO3, PO4 etc causing algae.

Her, Amano, Dupla, Dennerle.
 
#3 ·
I dont know if its true or not but from what I can tell my plants are doing just fine if not better without any type of ferts.

I used to be on a schedule for ferts. Macros one days micros the next, and the plants seemed fine.Tthen for some reason (lake of time) I started slacking on tank mantinence, and stoped ferts all together and I see no change in my plants. As a matter of fact they seem bushier and fuller now that ive stopped. Plus I have no green spot or algae of any type in the tank anymore.

I do use pressurized C02 with a pretty high PPM but it doesnt seem to bother the fish one bit. basically I have a high tech setup with close to no maintenence...lol

PC lighting @ 6wpg
Pressurized C02
Eco-complete substrate
I over filter, over feed and for some I am overstocked
I dont syphon all the substrate I slightly skim the top of it and get what I can, never going into the gravel.
Top off the water when it gets low and do a water change about once a month sometimes longer.

All my water parameters are perfect, plants are growing out of the tank and havent lost a fish in over a year besides one jumper a month ago. I might not be running the picture perfect setup but from my experiance its working great and alot less hassle. Ill probably get flamed for my maintenence schedule but like I said it works for me. Trust me if I thought the fish/plants/tank were unhealthy I would definatly be changing the way I do things...so far so good everything is nicely balanced the way it is now...
 
#5 ·
I dont know if its true or not but from what I can tell my plants are doing just fine if not better without any type of ferts.

I used to be on a schedule for ferts. Macros one days micros the next, and the plants seemed fine.Tthen for some reason (lake of time) I started slacking on tank mantinence, and stoped ferts all together and I see no change in my plants. As a matter of fact they seem bushier and fuller now that ive stopped. Plus I have no green spot or algae of any type in the tank anymore.

I do use pressurized C02 with a pretty high PPM but it doesnt seem to bother the fish one bit. basically I have a high tech setup with close to no maintenence...lol

PC lighting @ 6wpg
Pressurized C02

Eco-complete substrate
I over filter, over feed and for some I am overstocked
I dont syphon all the substrate I slightly skim the top of it and get what I can, never going into the gravel.
Top off the water when it gets low and do a water change about once a month sometimes longer.

All my water parameters are perfect, plants are growing out of the tank and havent lost a fish in over a year besides one jumper a month ago. I might not be running the picture perfect setup but from my experiance its working great and alot less hassle. Ill probably get flamed for my maintenence schedule but like I said it works for me. Trust me if I thought the fish/plants/tank were unhealthy I would definatly be changing the way I do things...so far so good everything is nicely balanced the way it is now...
You have found a technique that is working to your satisfaction, so there is no reason for you to do anything differently. This doesn't mean someone else will achieve the same satisfaction doing the same things. We all have our own expectations of our aquarium.
 
#4 · (Edited)
Christel Kasselmann says just that in her book Planted Aquariums - Creation And Maintenance (English edition), pages 102-105:
That is also the basis of Diana Walstads methodology, and Dutch aquariums going back decades. You achieve a balanced system with very slow growth compared to the methods today that pushes plant growth like they are on steroids. Extremely high levels of C02, daily additions of macro and minor nutrients to the point that a weekly water change is needed to get rid of the excess nutrient levels, and moderate to intensive light is like going on an eating binge and then sticking your finger down your throat. I find both methods interesting. I'm striving to find something in the middle.
 
#6 ·
Every setup is unique. Lighting, light cycle, water chemistry, maintenance
schedule, fish type / fish load, food type, feeding schedule, substrate
type, substrate age, plant types, plant volume - even the location of
the setup - all play a role in how it 'acts' and defines it's needs. To throw
another variable in it - these needs change over time.

The tank is alive, and it has a metabolism. If the intake and outtake
are not balanced, you will have issues.

So, can fish poop provide all the nutrients a planted tank needs?
In some cases it may - but think about all the variables listed above, and
the ones I havent listed - do you think you can acheive that balance?

IMO - thats nearly impossible. The only thing that you can do is to
'reset' the balance to neutral before the imbalance gets out of hand - work
at a speed faster than the tanks 'metabolism'.
 
#7 ·
IMO - thats nearly impossible. The only thing that you can do is to
'reset' the balance to neutral before the imbalance gets out of hand - work
at a speed faster than the tanks 'metabolism'.
"work
at a speed faster than the tanks 'metabolism'.

Can you define what you mean by that? We create an atificial balance in the aquarium and I would think creat the "metabolisim" by the parameters we set such as light and C02.
 
#8 ·
A tanks 'Metabolism' would be defined as sum of all chemical and biological processes that occur within the tank. Think of it as a single living organism.
You can speed up it's internal processes by adding light, nutrients and
increasing the temperature. Its not linear. Too much or too little of any
one of these can lead to the 'death' or 'ill-health' of the tank.

A tanks metabolism can be measured in days - since things move along
relativly slowly. If you make a change, say, add too much NO3, but quickly
do a water change to go back to normal params, within a short period of
time, the tank won't 'notice' the change. However, that same change over
a period of days, will have a effect on the system.

So let's bring all this back into fish poop perspective...
Low tech tank - slow metabolism. Fish poop provides certain macros / traces.
The amount of nutrients per day is fairly small, but it does not matter, since over time that adds up, and consumption is slow.
Everyone is happy for the time being - until you get a build up of something
and you get an imbalance. On a low tech system - this could be months.
However, by 'reseting' the system by doing a 1-month 50% water change,
you stay ahead and keep the system seemingly 'balanced'.

High tech tank - fast metabolism. Fish poop provides certain nutrients. Not
nearly enough or balanced. You'll need to add additional ferts to keep plants
growing. You will still eventually get an imbalance. To stay ahead of the game, you need to 'reset' the system at a faster frequency - 1-week 50% water change. Enter the Estimative Index.

So - to answer the question - Will fish wastes provide all macro + micro?
Maybe - depends on too many items - and chances you'll be able to
acheive that balance are minimal.

It took nature millions of years to create an eco-system.
To create event a partial eco-system in a glass-box is difficult at best.
 
#9 ·
A nice analogy. Certainly much to think about, but I do not agree that EI is the only way to go. You can be above the minimal light threshold and still not have to have extreme levels of C02 and nutrients to achieve a balance.

I think the better question for the original poster is can fish poop provide all the nitrogen and phosphate plants need? And, how do you determin how much they need? Nitrogen is the chief nutrient poop provides. How much trace minerals it would provide I think would be questionable under any circumstances.

A more accurate, relevant question is how can you visually determin the health and balance of the system? By the speed of the plant growth? Color? Amount of algae? Water clarity? These visual indicators and how they are interpreted are very subjective. One persons pride and joy is anothers horror. I think finding a balance is fairly easy. It is being satisfied with the results that is difficult.
 
#10 ·
One persons pride and joy is anothers horror. I think finding a balance is fairly easy. It is being satisfied with the results that is difficult.
What a statement. :wink: As I mature in the planted tank area, I find my results from 10 yrs ago would make me cringe today (even though I was quite satisfied back then). Experiencing the "bad" things that can happen over the years with different types of algae, fish behaviors, plant growth patterns, and new tank setups has helped me achieve the balance that currently suits my standards. Understanding the relationships between light intensity, CO2, nutrients, and plants (including algae) is paramount to success in this hobby. I just wish forums like this were present when I began with planted tanks.
 
#13 ·
There is no simple answer to your question unless you are just straight out asking if this fish food contains all macro and minor nutrients, and my guess would be no. Very unlikely. If your question is can your plants grow well enough to please you by feeding them nothing but fish food, then the answer is yes, maybe, or NO. How's that?
 
#15 ·
Fish waste has more than enough nutrients for plants. The problem is availability of those nutrients. In tanks with high light and CO2, plants grow faster than they can take up nutrients from the waste, which is why adding ferts to the water column is a common practice. In a low light, no CO2 tank, fish waste should be more than enough. That is my theory anyway.
 
#16 ·
If you think about a natural river or pond, there are lots of fish and lots of plants. But, there also must be a lot of beneficial bateria to break down the waste of fish to provide the macros and the micros. In a tank environment, everything is on a smaller scale. When I first started planting my tank not too long ago, I didn't think of putting in macros and micros because the fish would naturally provide it. The plants eventually withered and were down to the base. I recently took the bases of these plants and brought them to college with me where I have a plastic 15L box from Target set up so that they could recover. The base is 100% flourite and I dose NPK and micros from Seachem. The plant bases have now started to sprout new leaves and plantets with the edition of the fertilizers. So in my opinion, a regular tank environment probably will not provide enough NPK and micros for sustained periods of healthy growth.
 
#17 ·
In a natural setting, the fish load is extreemly small easily 1000 gallons per fish but probably much more. A river is basically a constant waterchange system, so very little bacteria is needed since most fish waste is washed away. Most plant nutrients are from run off into the lake or river.

Waht was your lighting and CO2 levels in that tank before you dosed ferts?
 
#22 ·
Extremely high levels of C02, daily additions of macro and minor nutrients to the point that a weekly water change is needed to get rid of the excess nutrient levels, and moderate to intensive light is like going on an eating binge and then sticking your finger down your throat.
:pound:

Classic!

NewGuy, you have some good answers in this thread.
Which answer works for you?

If you want as simple as possible, there is the Seachem Daily Dosage Schedule.
But that is one choice among, how many?
 
#25 ·
:pound:

NewGuy, you have some good answers in this thread.
Which answer works for you?
Havent dosed anything in about 2 and half months now, everything is just peachy. However about 2 week ago i stopped co2 injection altogether as well, this caused my pygmy chain swords to stop sending out runners(i think)

If you look at my tank pics, i replanted a few E. Tenellus on the right side hoping it will expand and cover the entire area as well. But i stopped co2 injection (was 1 bubblle/2sec) and now the chain swords stopped expanding, all other plants are fine and growing.

Trying to decide if i should increase my wpg from 96W to 192W or resume co2. This is baffling considering i just added 30 fish to my tank, 14 of them high co2 output rainbows.

hmm...co2 or light? each cost $200, but which would make my pygmy chain sword send out runners again? that is the question!
 
#23 ·
What a statement. As I mature in the planted tank area, I find my results from 10 yrs ago would make me cringe today (even though I was quite satisfied back then). Experiencing the "bad" things that can happen over the years with different types of algae, fish behaviors, plant growth patterns, and new tank setups has helped me achieve the balance that currently suits my standards. Understanding the relationships between light intensity, CO2, nutrients, and plants (including algae) is paramount to success in this hobby. I just wish forums like this were present when I began with planted tanks.
Spdskr, how many methods have you used and in which order did you go on the learning curve?
(If you can remember.)
I just remember Tom Barr's advice something along the lines of - try them all! And then use ________.

Wouldn't it be nice to just purchase a box and add water? You know, buy, open box, read directions, follow directions, have happy plants. Or there is the other method which is go to grad school for one of the sciences, learn about all the sub atomic particles - and then try. (cheeky grin).
 
#24 · (Edited)
Based on common planted tank wisdom I fertilized religously for years, but for the sake of experimentation decided to stop...and my tank has never been better. I use pressurized Co2 and 2.5wpg and the plants are growing out of the tank and virtually algae free. They are so clean, healthy and prolific I'm now selling cuttings back to the LFS, this was never possible during fertilization. I suggest trying it to see for yourself, you can always go back to fertilizing if your plants develop obvious deficientcies.
 
#26 ·
hmm...co2 or light? each cost $200, but which would make my pygmy chain sword send out runners again? that is the question!
I just followed your link to your 50 Gallon Planted Tank. That is just plain beautiful!
Now that the question is more specific, let's see what their answers are. Which approach? Biology? Chemistry? Light? High Tech? Low Tech? Seachem Excel? CO2? DIY? Let's see.
 
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