Sustainable Fishtank?

[MaxxxR]

Hello everyone,
I am creating a sustainable fishtank for a school project and need some advise. The tank will be self-sustaining meaning that the tank should be able to last 10 days without putting food into the tank or any other substance to help. The tank will be planted and will contain two types of fish, and maybe some crustaceans such as a small shrimp species. I haven't decided exactly how big the tank will be but i think around 20 gallons with an external filter and lighting system. Can someone give some fish and plant type suggestions as well as reasons behind them bearing in mind the fish wont be able to eat any outside food for 10 days. If anyone has anymore questions or inquiries please feel free to ask.

 

[StevenF]

What are the fish going to eat for 10 days? Are you going to intentionally starve the fish?  Once you figure that out you will need to determine the size of tank needed to supply the food the fish are going to eat.  How will you prevent water evaporation during the 10 days while still allowing aeration of the water.  Somehow the lost water will have to be replaced.

 

[NickAu]

Forget it, Cant be done, Even if the fish didn't die in the first 10 days they would soon after, Please do not do this.

 

[Jeremy180]

You're still allowed to provide care until the ten day period starts right? Otherwise I don't see how this could work.
Providing food is relatively simple, but it probably won't be ready in time for your project.
Step 1: Cycle a tank(at least 20 55 gal)  and keep cycling until an extremely heavy biofilm develops.
Step 2: Add an adequate light and VERY heavily plant the tank (it should resemble a Jungle with very little open space at all) with fast-growing low to medium light plants.
Step 3: add a few Cherry shrimp and let them build up a large colony (about 50-100 100-200)
Step 4: Add one or maybe two different species of very small rapidly breeding fish, preferably under an inch (2.5Cm).
These need to be unable to harm the adults, but could still eat the shrimplets and sub-juvenile shrimp, but not effectively enough to wipe them out.
(Steven's input would be most helpful here) and let them build up a fair population.
Step 5: (may not be doable, wait for Steven's reply) Add  a single dwarf Frog as an "apex predator"(it may wipe out the tank over time)
, A male Betta may also work as an alternative candidate (not both!), just be sure the "prey" has plenty of cover otherwise it could be wiped out.
Step 6: Finally, do a large water change (about 70%) the Day before the project begins.
In theory, the shrimp should eat the biofilm, the small fish eat the juvvie& baby shrimp, and the Apex predator would cull from both, and the plants would remove nitrates somewhat while providing cover to prevent all the "prey" from being eaten at once.
Of course, it will probably need at least some fine-tuning, but I think the basic principle is sound IN THE SHORT RUN,
although it would probably almost certainly break down long term.

 

[Bubbelzzz]

10 days isn't that bad actually. In the dry season, a lot of aquarium fish species won't eat as much as would happen under normal circumstances. When looking at aquariums we can see that too little food doesn't occur very often either. Overfeeding happens more often.
If you want to do this though you'll need to give the animals time to get used to the tank. So you will need a period upfront to make sure the fish are completely healthy. This will namely only work with fish that are healthy. Otherwise, they are very likely to become ill and die. Some fish can survive for weeks without food or other maintenance. However, I would not recommend doing this. Even if for some reason fish can't get food for a couple of days, make sure this food-less period isn't longer than 2 weeks.
 
It is important to note that this is not the case for all fish. For example, seasonal fish such as Pseudomugil gertrudae will have a harder time in surviving than fish that are used to surviving in the dry periods, such as corydoras species. 
 
So maintaining it for 10 days shouldn't be an issue, when the fish are healthy. But, again, I wouldn't recommend it.
 
As above mentioned, you could still provide them with food by adding fast breeding fish or even better some shrimp.

 

[BettaPonic]

Semi aquatic plants such as Pothos remove a huge amount of nutrients. They are not limited by CO2 in the water.

 

[StandbySetting]

Possible - but very difficult to replicate - take a read of Jeremy Gay's article on Decembers issue of practical fish keeping.