# Self-Sustained (almost) Tank... Possible?



## jakediamante (Feb 9, 2011)

*One more question-*

Also- what other kinds of invertebrates are there, that would make good fish food and be able to reproduce in an aquarium?


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## Mxx (Dec 29, 2010)

Tricky one that, but it's something I'd considered myself to some degree though not in entirety. One possibility might be to establish a refugium which would have your breeding stock of bugs, and an overflow into the tank with a screen which is small enough to allow the juvenile bugs to get through, but not the adults. Otherwise I think your fish might be pretty effective at immediately wiping out the entire bug population. This could be accomplished via a 3D background which is set forward a few inches, and which has lighting and plants or algae growing behind it. That would be similar to an algae scrubber, which many reef aquarists use, and a large amount of algae or plant growth there might be able to support some type of a self-sufficient bug population. A powerhead could pull water in from the tank, and then the screened outflow into the tank might supply a steady stream of bugs. 

I would suggest an enriched mineralized top soil, which should have sufficient nutrients to keep the plants happy for a decent amount of time as long as you had low lighting. 

Getting everything to balance perfectly might be quite a struggle though, and you might need to add nutrients in order to keep the plants from depleting everything in order to to keep the bug population thriving and the fish fed.


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## boringname (Nov 11, 2010)

i've heard of other people trying this and what usually kills it is they get bored with how few fish can live in such a tank. If you can live with just two small fish in a big tank I think it can work.

""5. Worms- is it possible for apistogrammas to eat them, or will they just hide in the gravel forever?"

Their only motive for coming above the gravel is to get oxygen. Thats why they stick their tails up and they stick more up the less oxygen their is in the water. Some fish will work through the gravel and get them anyway.

http://www.aquaculturestore.com/fwinverts.html

"Freshwater plankton - 200 ml culture - Ostracods, daphnia, rotifers, ceriodaphnia, copepods, amphipods....a nice varied selection."

Twenty bucks is too much for me to spend on a whim but I've always thought about buying this package of plankton and micro crustaceans to get a tank started. Of course I think you will get copepods anyway just from tap water, the chlorine doesn't kill everything.


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## shrimpo (Aug 2, 2009)

Mxx said:


> Tricky one that, but it's something I'd considered myself to some degree though not in entirety. One possibility might be to establish a refugium which would have your breeding stock of bugs.


+1 on refugium, I used Hang On Back refugium in a 10 gallon saltwater to raise amphipods beside other critters.
Here is some pictures of the tank and the HOB refugium.


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## snafuspyramid (May 27, 2010)

I imagine you'd need a tremendous amount of cover - lots of Java Moss, etc - for the bugs to stand any chance of survival, since almost all fish will eat well beyond hunger and just love killing anything small and wiggly. And that will be impossible to sustain without fertilization, nothing short of a bug plague would produce enough waste.

While I think a refugium is a good idea, I think it could be achieved with heavy planting - but again, that would require decent fertilisation. 

It would also depend on the mineral content of your water supply. Are we assuming water changes here? How much? Etc...


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## OverStocked (May 26, 2007)

The trouble with this plan is that in a small atmosphere like our tanks, the apistos will devour your critters in no time and you will be left without anything resembling self sustaining.


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## jakediamante (Feb 9, 2011)

*More Water Details*

Ah yes, thanks for reminding me, snafuspyramid, water changes were another huge question I had...

I am starting with Distilled water, and Eco Complete substrate, which I suppose has some nutrients. 

Will I be able to get away with enough of a chemical balance between the bugs, plants, fish, and (obviously) bacteria, that I wont have to do water changes (or just not very often)?


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## Mxx (Dec 29, 2010)

jakediamante said:


> Ah yes, thanks for reminding me, snafuspyramid, water changes were another huge question I had...
> 
> I am starting with Distilled water, and Eco Complete substrate, which I suppose has some nutrients.
> 
> Will I be able to get away with enough of a chemical balance between the bugs, plants, fish, and (obviously) bacteria, that I wont have to do water changes (or just not very often)?


Oh dear, we're back to opening up that can of worms!... Look up the Why do water changes? or Zero water change planted discus tank proposal threads which had some helpful discussion, but wildly divergent opinions as well. One of the gurus here, Tom Barr has managed many a successful no water change planted low-tech tank with higher stocking loads then you are talking about. The plants would more than mop up any nutrients produced by that small an amount of fish, so to achieve lush plant growth you very well may need to dose fertilizer or at least add fish food to the tank, but that depends upon what your goals are. 

By the way, you can't use straight distilled water, you'd need to either mix that with tap water or remineralize it with some of the commercially available remineralization mixes. 

When I'd asked about the best way to maintain a low maintenance tank everyone had suggested using simply mineralized top soil, which could be topped with whatever substance you like, be it Eco Complete or something else. I'm not sure if Eco Complete is as rich as that would be. 

From everything I've gathered thus far, the ecology may work out well enough that you could achieve a stable balance at which point water changes could even be detrimental as the sudden change could interrupt the balance and trigger algae. Carefully review the low-tech tank threads for help. You may need to be aware of some necessary techniques and monitoring such as including a small enough amount of crushed coral that it will prevent your Ph from falling precipitously in time as the metabolic processes consume the minerals in the tank and lower the Kh.


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## Sharkfood (May 2, 2010)

Wouldn't the plants eventually take all the nitrogen out of the system, or do you trim them and allow cuttings to rot in the refugium? It seems to me that you would have to add food or some source of nutrients occasionally to keep nutrients high enough for life to exist. Unless of course, plants are being eaten, or dying, recycling their components back into the water to keep the "bugs" going.


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## WallaceGrover (Jan 15, 2011)

IMO you really need to define self-sustaining.

I mean, you'll have to at LEAST do water top offs and maybe once in a blue moon add some nurtients...


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## wendyjo (Feb 20, 2009)

Raising shrimp may be a good food source as long as the adults are big enough not to be eaten by your choice of fish but the babies are small enough to fit in their mouths.


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## Mxx (Dec 29, 2010)

Check this thread - http://www.plantedtank.net/forums/low-tech-forum/99473-low-maintenance-ecosystem-tank.html


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## Danh Vu (Jul 3, 2010)

A self sustaining ecosystem might work besides topping off water. 
Is appearance an issue?


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## Solid (Jul 19, 2009)

To make this possible you would need a really large tank with lots of hiding places for the shrimp/food. In the end I think you would either need to feed the fish or feed the plants. Some people get away without fertilizing by providing enough fish waste. But with tiny fishload you would need the plants wouldn't get enough food.


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## jakediamante (Feb 9, 2011)

*thanks guys*

Ok to clarify-

I do plan on topping off when necessary, with some RO water, probably.

I will be fertilizing as needed. I'm reading about all that on that forum...

Appearance-wise, I'd like it to be an attractive planted tank, with a few different species of plants- java ferns and moss, anubias to start out with, and I'll add from there.

In reality, I'm not insisting on a 100% self-contained unit. It's for curiosity, but also, I'd like to get it to the point where I could possibly leave it alone and let it do its thing for a couple weeks, and just watch a sort of wild, natural ecosystem.


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## WallaceGrover (Jan 15, 2011)

It probably would not be extremely attractive if you truly don't mess with it. Plants would overgrow one another, bunch up, dead leaves, etc....


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## H2OLOVER (Apr 29, 2010)

I have a 30gallon tall with 4 palmed sized angelfish, 4 half dollar sized angelfish, 3 bosemani rainbows, 3 blue rainbows, 2 rams, 4 flying fox, and a cigar shark. High tech with CO2, heavily planted, No Refugium, Its run by an xp3. my ph is around 6.5. my ammonia and nitrite is 0, Nitrate is < 10ppm...i feed 4-5 cubes of Hikari Bloodworms a day.
I havent done a water change for about a month. and it seems like the nitrates keep going lower and lower


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## wkndracer (Mar 14, 2009)

H2OLOVER said:


> I have a 30gallon tall with 4 palmed sized angelfish, 4 half dollar sized angelfish, 3 bosemani rainbows, 3 blue rainbows, 2 rams, 4 flying fox, and a cigar shark. High tech with CO2, heavily planted, No Refugium, Its run by an xp3. my ph is around 6.5. my ammonia and nitrite is 0, Nitrate is < 10ppm...i feed 4-5 cubes of Hikari Bloodworms a day.
> I havent done a water change for about a month. and it seems like the nitrates keep going lower and lower


Wow! (that's all I can post)


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## plantbrain (Dec 15, 2003)

jakediamante said:


> Ok to clarify-
> 
> I do plan on topping off when necessary, with some RO water, probably.
> 
> ...


I define levels of sustainability.
Minimalization of input/outputs.

So less input from the aquarist, and less output for the tank.

2 biggest inputs that are hard to avoid:
Evaporation and fish food(common).

Out puts: filter cleanings, and plant trimming(rare)

A good idea for folks interested in this approach is to use emergent and floating plant species, this makes it very easy to handle a larger biomass of fish.

Eg:









No issues with higher light or CO2.
So plants grow faster than submersed species with CO2 and the uptake is higher.

If you have few fish, then something like this might be easier for you:










Depends on your goal and the fish you plan to keep.


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## astrosag (Sep 3, 2010)

Its very difficult to envision a scenario where you will not have to add fish food to the tank without having to micromanage the "live" - in tank- fish food...which runs counter to your sustainability goal (which I read, from your posts, as a mix of sustainability and hands-off tank keeping). Like posters before me have stated, this makes it very important to define the term "sustainability".

Though Mr. Barr doesn't explicitly state it, I think he's absolutely right...you won't avoid fish food or water top-offs. Think of the gravity of what you are trying to replicate here....even for two small fish. A fully enclosed, nearly fully sustained ecosystem. Either way, you're going to end up micromanaging/managing something on a regular basis. It may be the refugium or the tank itself.

A simple example would be a tank with some algae eaters sitting under a ton of light or in sunlight. With minimal filtration changes and top offs, you probably wouldn't need to supply much to the tank in terms of food - but I don't know anyone who would consider a algae infested, green-walled tank with a couple algae eaters you cant see as an idea for a good fish tank . I say this because I had a friend that kept this nasty fluval tank in the sun...algae everywhere, 1 algae eater and only topped the water off (too lazy to clean it - yup it was that dirty). Of course the sun may have excluded it from being "sustainable" as its no longer a closed system - again, must define sustainability.

Of course, in cases like these, I love to be proved wrong . But keeping things alive on their own in a fully closed system is no small task.


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## EricSilver (Feb 23, 2004)

It would work best outdoors. 

This past summer I had remarkable success with my near zero maintenance water hyacinth container garden, into which I added bettas, feeder guppies and ghost shrimp. All survived mostly on naturally ocurring mosquito larvae; black worms I added once/week; and, likely, baby shrimp. 

Right now the hyacinths, a mat of duckweed, a large crypt, and a small amazon sword are in my 29, along with the 7th generation of guppies from my original pairs and a female betta large enough to swallow the guppies whole -- adults and babies. 

There is no filtration and I do no water changes. There is a 65W overhead light that barely penterates past the hyacinth leaves. The other plants thrive on sunlight through a nearby window. Surprisingly, algae is not an issue beyond a loose film I occiasionally wipe from the front glass

In May I am moving the entire tank outside (without the canopy or heater, but with the CO2, which they will need in direct sunlight). The inhabitants did very well in opaque plastic barrels last year and survived extremes of temperature. This year I want to be able to observe what's going on below the surface.


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## H2OLOVER (Apr 29, 2010)

wkndracer said:


> Wow! (that's all I can post)


roud: thank you


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## astrosag (Sep 3, 2010)

EricSilver said:


> It would work best outdoors.
> 
> T


Agreed. But this probably doesn't fit into the sustainability mold too well. In terms of maintainability its near perfect. Like you said, bugs, larvae, sun...all make it an open system.

I like your idea though - wanted such a pond type in my backyard always.


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## gbose (Nov 21, 2010)

JakeD,

I think you're looking for the philosopher's stone ... the self-sustaining tank. I think it depends what you mean by 'self-sustaining'. You might want to check on 'Naturally Planted Tank', as I hear they need very little maintenance. 

But I think Danh V is on target with his question about tank appearance -- I've heard NPTs are quite untidy.

Just my 2cents...

GB


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## flyjsh (Jun 2, 2008)

As a pure experiment, I have a corked 1.5 liter wine bottle with seasoned substrate, moss, trumpet snails, and daphnia in a windowsill. It ran very well for about 18-20 months ... until it got badly chilled while I was gone.


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## BigTom (Sep 16, 2011)

Hi, 

I have a 3'x1'x3' tank that is self sustaining, except that I sometimes add dead beech leaves to feed the critters and add nutrients. No water changes, just top-offs.

Currently supporting 4 otos, 7 Bororas maculata and 6 Parosphromenus sp. 'sentang', but I think Apistos are a bad choice, they're too voracious.

More info over on UKAPs if you're interested - http://ukaps.org/forum/viewtopic.php?f=35&t=14521&start=130

Also check this out, where I got some of ym inspiration from -

http://www.tuncalik.com/2009/09/biotope-in-my-study/

EDIT - oops, didn't realise how old this thread was! Thought it was current after Mxx posted a link ove ron UKAPS...


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## Storm (Aug 7, 2011)

To the original poster:

I think you must be thinking of Diana Walstad's method for no maintenance or low maintenance planted tanks. She uses soil and low-tech methods and heavily planted tanks as a way to minimize water changes. Her book has a lot to say about chemistry and can help you out if you're trying to accomplish something like this.

The difficulty is this:

Fish need food to eat.
Plants need food to eat, and can get this from fish waste, but you need a large enough amount of fish waste to feed the plants.

So, you do have to input food into the system. There is no real way around this. You also need to get the balance right. Too much food in the system and you need to do water changes to drop the nitrate levels. Too little food in the system and your plants will starve and wither and die, or else you'll have to supplement with plant fertilizers.

It's very difficult to make a perfectly balanced ecosystem in anything less than a small pond, so that's why most of us do fert dosing for the plants and water changes for the fish.


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## Mxx (Dec 29, 2010)

Storm said:


> To the original poster:
> 
> I think you must be thinking of Diana Walstad's method for no maintenance or low maintenance planted tanks. She uses soil and low-tech methods and heavily planted tanks as a way to minimize water changes. Her book has a lot to say about chemistry and can help you out if you're trying to accomplish something like this.
> 
> ...


I must in part dissent from that opinion. I think that flora and fauna will in time achieve a balance between themselves over time. I mean, they've only been working on perfecting that for about the last four billion years, with at least a reasonable level of success achieved finally in the last billion years, apart from one invasive species now - **** sapiens - which are currently threatening to severely disrupt the system's stability. 

Whether the system requires the input of additional nitrogen over time is a good question certainly. The anaerobic bacteria present will through denitrification produce nitrogen gas which is gassed out of an open system. I'm not actually sure what all the final byproducts of the nitrogen which plants consume are, and whether that is expelled out of the system in some particular form as well. 

And there are certain species of plants and bacteria capable of nitrogen fixation, which would thus self-refertilize the system just from the air. However, these are species such as legumes, clover, alfalfa, sugar cane, and blue-green bacteria, which are not usually present in our systems in significant quantities, unless you were to grow legumes in your tank as emersive plants? However, the floating plant Azolla does provide nitrogen fixation. 

If you're using a MTS substrate then you nevertheless might have several years supply of nitrogen already in the soil though, much of which will be repeatedly cycled back into the substrate as plants die, and are consumed by microfauna which are consumed by fish, and then returned to the substrate upon leaving the fish. 

In any case, unless the fish are breeding heavily then I expect it will be the plants not the fish which will be affected by limiting factors (ignoring for discussions sake the store of nutrients in the soil), and therefore the plants would only be able to grow and continue to spread at the limiting rate at which the fish and other fauna (including bacteria?) are recycling nutrients back to them. 

So as long as you continue to have plants present then clearly there are still a certain amount of nutrients present and cycling in the system, even if some might happen to exhibit signs of deficiencies. But if the plants start to all disappear after time then perhaps the nitrogen is all getting cycled out of the system and would need to be replenished?

But if you have sufficient nitrogen fixation happening in some form in your system, then perhaps the only input necessary, (the same as with our planet), is sunlight.

I'm just wondering now how well this would work if you completely sealed the top of the tank...


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## WallaceGrover (Jan 15, 2011)

BigTom said:


> Hi,
> 
> I have a 3'x1'x3' tank that is self sustaining, except that I sometimes add dead beech leaves to feed the critters and add nutrients. No water changes, just top-offs.
> 
> ...


WOW :drool:, this is probably the best tank I have EVER seen. Like, it follows everything I admire in fish tanks: light-stocking, attention to microfauna, emergent plants, just WOW. It's not in the style of Amano but I think this type of tank could easily rival it since it is not reliant on superficial looks alone. If it were a biotopope you would be god...


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## astrosag (Sep 3, 2010)

Mxx said:


> I must in part dissent from that opinion. I think that flora and fauna will in time achieve a balance between themselves over time....


For this to happen, you have to a stabilized system - in that inputs are stable over time. 

The largest problem here is not maintaining the plants nor is it maintaining a level of water quality that is suitable for fish. The problem here is with the fish themselves. I don't see how one would get around having to feed the fish and thus chucking the notion of self-sustaining out of the window.

Top-offs and feeding are almost entirely unavoidable. The best chance of course, is to have an incredibly heavily planted tank with very very little fauna-mass...something extraordinarily unproportional. 

*BUT* even then, in my opinion, all you are doing is *delaying* the inevitable need to input something into the system. Two micro fish and whatever method of slow dripping food to them doesn't imply a self-sustaining system - even if you don't have to change or add/detract anything for up to a year.

In my opinion, if you did seal the top and let it be, you'd be coming back to a disaster. It's pretty naive, just to being with, to think we can replicate an ecosystem with nothing but some electricity and the right choices of plant and fauna. You're either going to break the notion of self-sustaining (or push it beyond recognition) or you're going to need some extraordinary efforts to make this happen. To begin with, you can most definitely chuck the idea of doing this in a small tank out the window.....


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## astrosag (Sep 3, 2010)

Mxx, you cover the nitrogen cycle thoroughly but you don't state how or what the fish are feeding off of..or am I missing something?

Again, the question isn't if you can provide a sustainable (read livable) environment for fish given that all you do is top off the water and add food. Anyone could do that if they had enough plants in the tank relative to the amount of animal mass. (i.e.: I could put one harlequin rasbora in a 150G tank filled to the brim with flora and that guy would probably live out his life with me only having to add food and top-off the water level.

The question is self-sustainability and that is almost an infinitely larger leap.


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## Mxx (Dec 29, 2010)

Astrosag - The food for fish issue is a bit of a separate question, and one which I'd certainly wondered about myself. Check out post 28 here by Big Tom, and his links to his own such tank and the one that had inspired his. 

It seems that he has been able to cultivate the necessary level of microfauna, - Daphnia, shrimp, cyclops, etc. and has sufficiently heavy cover that the microfauna population has remained stable and has fed a proportionately quite small collection of fish within his tank. So the practical example of his tank apparently demonstrates that it can be done successfully. He does do top-offs, and adds dried beached leaves, but it seems that apart from light those are the only two inputs, which is in any case quite minimal. That and he does have a small powerhead to break up the surface biofilm. 

It's of course not an actual replica of any ecosystem, but if you create optimal conditions for microfauna to thrive then these examples demonstrate that it can achieve sufficiently intensive growth to sustain both itself and small species such as a few Badis and Licorice Gouramis. Most people of course wouldn't be happy with such stocking levels. But I think the concept could be even more successful if you had an invertebrate refugium with a small flow into your tank. Reefers it seems use such a thing to provide a slow feed of live arthropods to finicky fish species. 

An entirely sealed relatively small vessel is a different matter, and might only work with species which would thrive on nothing but algae and decaying plant matter, which thus could perhaps work with cherry shrimp so long as they didn't start to breed. That might also require something such as Azolla floating plants to provide nitrogen fixation and complete the cycle. Cyanobacteria could, but that's perhaps not desirable either for various reasons. I'm not exactly sure how that would work actually, but I've been setting up a small trial with a few 5 litre jars. 

In any case, the circle of life is of course a cyclical thing, rather than a linear thing which is how things like the nitrogen cycle are often described to us in the hobby. And (unless you're religious), plenty of fish populations seem quite stable in lakes and ponds without some hand of god to feed them, and it's just a matter of proportionality of course, as you'd mentioned.


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## kuni (May 7, 2010)

Mxx said:


> And (unless you're religious), plenty of fish populations seem quite stable in lakes and ponds without some hand of god to feed them, and it's just a matter of proportionality of course, as you'd mentioned.


Religious....or a population biologist. Natural populations are rarely stable if predation is involved, unless by stable you meant "changes by large amounts but in a somewhat predictable manner".

http://en.wikipedia.org/wiki/Lotka_volterra

Minor digression. 

Personally, I think a tank like this is only doable if you wanted a small-crustacean-only tank, or were willing to go with a single badis, which would be too small to eat adult amphipods. You would still have to feed + fertilize + top off, though. Is that self-sustaining? You decide.


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## Mxx (Dec 29, 2010)

Good point, but not quite the case with the examples we're discussing. These examples don't actually seem to have self-sustaining predator populations, or at there hasn't been any mention of the Badis/etc reproducing, but if they did they also happen to eat their own fry once free-swimming. So in that sense, if you have to eventually replace the fish once they've completed their lives then it's of course not a completely self-sustaining system. That does however mean there is a stable and fixed predator population. The prey population might rise and fall, and if it falls too low that might end up reducing the predator population to a more stable level to where the prey can then fully replenish themselves. 

I can't make claims personally on whether it works or how well it works though, but there are two examples here where it does seem to have worked for them.

Would a fair sized tank with a half-dozen Badis, and a few dozen cherry shrimp perhaps be an otherwise self-sustaining population, as the adult cherries would be too large to eat, even if you perhaps did have to at some point replace the adult cherry shrimp and Badis?


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## kuni (May 7, 2010)

Mxx said:


> Good point, but not quite the case with the examples we're discussing.


That was my point - once you have the ability for the predators to reproduce, things probably won't last. Some of those badis fry may survive being eaten, etc.

With no predator reproduction, I think it's doable.


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## aman74 (Feb 19, 2007)

Mxx said:


> He does do top-offs, and adds dried beached leaves, but it seems that apart from light those are the only two inputs, which is in any case quite minimal. That and he does have a small powerhead to break up the surface biofilm.


That's the problem though. You had challenged the notion that a self-sustaining system wasn't viable. I think that's all Astrosag was replying to. I enjoy your posts and think you're right on with a lot of your ideas. It's just that you were laying out a case for self-sustaining systems, and then listed all the inputs that shows it's not.

Astrosag gave a good example with the 150gal tank and one tiny fish. Obviously you wouldn't have to do much to keep it going, but the point is you have to do something. Just because it's stretched out over time or made minimal doesn't make it any less true.

BigTom's tank is absolutely awesome I just read that whole thread and I'm truly inspired!



Mxx said:


> Would a fair sized tank with a half-dozen Badis, and a few dozen cherry shrimp perhaps be an otherwise self-sustaining population, as the adult cherries would be too large to eat, even if you perhaps did have to at some point replace the adult cherry shrimp and Badis?


So funny that you mention this! I actually just wrote about that in the other thread. That's been an idea of mine for quite some time! Also, was wondering about puffers, but I think they may eat the adult shrimp?


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## Gold Finger (Oct 13, 2011)

Hi Jake. Hi all. 

I am trying something similar, though less ambitious. I am happy to add food, but want to to achieve a tank which won't produce too much net nitrate if I leave town for a month . One that rarely needs water changes (someone can top off water for me, and I use an auto feeder). I am brand new to planted tanks and don't grasp how much nitrate they can absorb.

Here's what I have up and running so far: a 70 gallon tank with a soil base, some terrestrial plants with water roots hanging off the rim, a sponge filter, and a fat goldfish.

Here's what I plan: put some vals in there and let em go nuts. Then start hacking them out when they have taken up too much space.

Here's my concern: This fish comes from beefy stock. It is young now, but some of his full grown kin are around 10". That's gonna be a lot of ammonia. I feel, right or wrong, that anything over 20ppm nitrate will stunt goldfish).

ps. I would like to keep as much free swimming room as possible.


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## Gold Finger (Oct 13, 2011)

Oh, and to answer your original question Jake: yes, an almost self sustaining ecosystem is possible. I realize that you are not talking about a perpetual motion machine here, and imagine that you too understand entropy.


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## Alyssa (Sep 16, 2011)

Well ... I recounted an experience that I had as a small child that was what sort of got me to fall in love with the concept of a self sufficient enclosed biostructure somewhere on this forum.

So I'm not really proud of myself, but when I was a kid, I got tired of keeping the guppies and when the tank finally died down to the LAST guppy ... I was faced with killing it or getting more or just keeping it alive all by itself. I couldn't bring myself to flush it or kill it, so I grabbed a 12 oz glass from the kitchen - filled it with tank water, and put the guppy in it and then shoved it into a dark corner of my bookcase.

(I really hate that this was a decision I made - it was a horrid thing to do!)

All I did was top it off for months. I guess I was waiting for it to die so that the problem would be resolved.

Anyways, fast forward 9 months - I figured it would be dead and I could just deal with whatever was in the glass - and it was covered in algae ... thick algae cap on the top ... concealed a very FAT and surprisingly active and seemingly content guppy.

No light, no heater, no food, NOTHING. It created it's own little perfect biosphere - it ate the algae, the algae gave it oxygen, the fish waste gave the algae nutrients, and evidently that worked out into a balance that I honestly think had I just kept going, would have gone on just fine.

But I was so impressed (and guilty) that I gave it a 10g tank for the remainder of it's days and coddled that thing something fierce. But ... it sparked a true and genuine deep life-long interest in managing and balancing eco-structures ... and since the only ones I will probably ever get to do are the ones I create ... that's what I do.

But anyway ... that guppy showed me that it was indeed possible to do. And you don't get much smaller than a 12 ounce glass. And 9 months impressed the heck out of me even as a kid, and to be honest, it still does. If I hadn't seen it myself, I wouldn't believe it lol.


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## Steve001 (Feb 26, 2011)

Alyssa said:


> Well ... I recounted an experience that I had as a small child that was what sort of got me to fall in love with the concept of a self sufficient enclosed biostructure somewhere on this forum.
> 
> So I'm not really proud of myself, but when I was a kid, I got tired of keeping the guppies and when the tank finally died down to the LAST guppy ... I was faced with killing it or getting more or just keeping it alive all by itself. I couldn't bring myself to flush it or kill it, so I grabbed a 12 oz glass from the kitchen - filled it with tank water, and put the guppy in it and then shoved it into a dark corner of my bookcase.
> 
> ...


I like happy endings.


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## Gold Finger (Oct 13, 2011)

plantbrain said:


> I define levels of sustainability.
> Minimalization of input/outputs.
> 
> So less input from the aquarist, and less output for the tank.
> ...


Thanks Tom, 

Any other tips on maximizing nitrate consumption? I want to be able to house as much fish as possible and export as much nitrate as possible without packing the entire tank wall to wall with plants.


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