# Does fish poop in large quantities contain all the nutrients needed?



## dubvstudent (Jan 10, 2009)

The content of the feces will depend somewhat on the food. Cheaper or lower quality foods will tend to lead to high phosphates if proper husbandry is lacking. In other words, i feel that what is coming out probably is highly correlated to what is going in. 

Simply put, IMO, I do not feel that the fish excrement is supplying ALL the nutrients the tank needs, but, most moss will still do just fine under less than ideal conditions. Low tech-ers have been doing it successfully for years.


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## hedge_fund (Jan 1, 2006)

dubvstudent said:


> The content of the feces will depend somewhat on the food. Cheaper or lower quality foods will tend to lead to high phosphates if proper husbandry is lacking. In other words, i feel that what is coming out probably is highly correlated to what is going in.
> 
> Simply put, IMO, I do not feel that the fish excrement is supplying ALL the nutrients the tank needs, but, most moss will still do just fine under less than ideal conditions. Low tech-ers have been doing it successfully for years.


But what if I wanted to do "ideal" supplementation? Would enough poop be perfect or is it lacking macros/micros etc.


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## WallaceGrover (Jan 15, 2011)

I think fish poop would give you your N and P in sufficient quantities, but I don't know about potassium and micros...


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## dubvstudent (Jan 10, 2009)

hedge_fund said:


> But what if I wanted to do "ideal" supplementation? Would enough poop be perfect or is it lacking macros/micros etc.


Good question. You would probably have to consider the form too. i.e. what type of nitrogen and phosphate containing compounds are occurring and how readily are those used by plants.


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## Yo-han (Apr 15, 2010)

dubvstudent said:


> Good question. You would probably have to consider the form too. i.e. what type of nitrogen and phosphate containing compounds are occurring and how readily are those used by plants.


I think, in the end it will all be converted to PO4 and NO3 at some time by bacteria. So as long as you feed more than your plants use phosphate and nitrate won't be a problem. You can steer the amount of nitrate and phosphate by your cleaning schedule and the type of food. I wrote a few articles about it here: http://www.aquaticplantcentral.com/forumapc/filtration/84781-biological-filtration-translated-dutch.html

But traces like iron are low in most foods so this will run short in the long run. You can compensate by adding liquid traces or adding capsules into the substrate


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## kribkeeper888 (Oct 8, 2011)

Maybe nitrates, But certainly not for anything else. Its not healthy for your fish to be in a tank with that much fishpoop anyway lol. Get some ferts for dosing if you want nutrients in your tank. Its also not healthy for your fish to be gasping from co2.


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## pandacory (Apr 18, 2011)

out is usually some modified form of in...

all of the reading i have done indicates that Fish poo, whether it is their diet or not, is notably lacking mainly in Potassium, iron, magnesium, manganese and calcium, any of which can cause plant nutrient defficiencies, but moss will probably be ok. other defficiencies are probably linked highly to diet, but everything I've read says the same thing about the notable lacking parts regardless of diet. Obviously I do not have my own expensive lab to confirm.

remember, trimming and removing plants from the system is a nutrient export

changing the water is a nutrient export

topping off, with anything other than RO water is a nutrient import.

food is a nutrient import

dosing is a nutrient import

decomposing organics is nutrient recapture/conversion


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## BBradbury (Nov 8, 2010)

*Fertilizers*



hedge_fund said:


> Hi. I have a moss growout tank that gets medium light and very high Co2. The co2 is so high that the fish generally begin to gasp for air in the last hour before the lights go out. With that said, I do not fertilize with anything and have no algae at the moment. The fish do poop in there obviously but is there anything else that I should be supplementing which is missing from the poop? The fish get fed twice a day and are constantly pooping....my concern is that there is perhaps a missing nutrient that does not come in poop.
> 
> Any comments please?
> 
> thanks.


Hello hedge...

I keep low to moderate light plants and emerse the roots of some land plants in my tanks and if you feed your fish a balanced diet, I don't think there's a better, long term fert available. I do dose a liquid source of the "trace elements" every week, but just a little, because I only feed my fish two to three times a week and I don't want my plants to be under nourished.

B


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## wendyjo (Feb 20, 2009)

"The co2 is so high that the fish generally begin to gasp for air in the last hour before the lights go out. "

^ This makes me feel really bad for your fish - what a life.


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## hedge_fund (Jan 1, 2006)

wendyjo said:


> "The co2 is so high that the fish generally begin to gasp for air in the last hour before the lights go out. "
> 
> ^ This makes me feel really bad for your fish - what a life.


Can't be that bad if they look extremely healthy and breed like crazy.


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## lauraleellbp (Feb 3, 2008)

It's all about balance- yes, it's possible to set up a tank that does not need additional ferts- if you stick with lower light levels (plants grow more slowly and therefore the nutrient demand is not as high) and slower-growing plant species.

If you're running a higher light setup, chances are at some point your plant growth is going to outstrip the available nutrients and you'll start running into problems.


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## Diana (Jan 14, 2010)

As I improved conditions for the plants with better light and carbon (Excel and DIY) the first nutrients they needed me to add were potassium and iron. That plus heavily stocking levels (so lots of mixed foods) kept the plants going pretty well. 

Some tap water (perhaps well water) from high mineral areas may have some potassium. 
I would grow a test plant such as Java Fern. It shows some really distinctive potassium deficiency. That is how I monitor my tanks now.


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## taiwwa (May 6, 2012)

I've been experimenting with feeding fish chicken.

Because feeding them frozen brine shrimp or blood worms is annoying because you have to break up ice. Also, per pound that stuff costs the same as sushi.

Now, I believe that chicken contains a fair amount of potassium, which is a common deficiency in planted tanks.


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## xenxes (Dec 22, 2011)

I think fish poo supplies sufficient macro, and fish food supplies sufficient micro. Heavily planted = you can feed generously.


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## HybridHerp (May 24, 2012)

I think it would be safer though to just dose ferts than rely on fish poop. I feel like it also might really on the kind of fish you are keeping. I could maybe see it done with a bunch of small shoaling fish, but in a tank with larger fish, man their poops are slightly terrifying to look at. That and, I'm not so sure how well the plants would absorb a bunch of large poop either.


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## Gorglefrumpf (Aug 20, 2012)

taiwwa said:


> I've been experimenting with feeding fish chicken.
> 
> Because feeding them frozen brine shrimp or blood worms is annoying because you have to break up ice. Also, per pound that stuff costs the same as sushi.
> 
> Now, I believe that chicken contains a fair amount of potassium, which is a common deficiency in planted tanks.


Are you sure that chicken won't cause problems for your fish?


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## taiwwa (May 6, 2012)

Gorglefrumpf said:


> Are you sure that chicken won't cause problems for your fish?


they seem fine so far. I mean, I'm not so sure how a dead bloodworm is really that different from a muscle strand. I of course try to get the leanest bits possible. It's fun watching them pick bones clean.


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