Tank Ecosystem

[Suricate]

The concept of ecosystems and how the parts that form them interact is facinating to me. The facination increases when one is dealing with a closed system like in a tank.

Is it possible to create the type of environment in a tank where one organism (fish) feeds off another (smaller fish or plant) I mean on a macro scale, I'm not talking about the ammonia, nitrate, algea etc type things although these are very integril parts of the whole.

 

[Peter Lovett]

The short answer is yes.

I have been running an experiment now for over three years.

I had a spaer pair of Apistogramma "apache" and a two foot tank with nothing in it but some Cabomba the tank was sed with daphnia and left for tow week and then the Apache where put in and from that moment to this they have never been fed I am now on what i think is the F1 population. But there are at least 2 pair of spawning fry and about 20 to 30 fry.

The reason for this experiment is because I plan to build a tropical pond whitch will be about 150 sq/foot whitch will be a close ecosystem.

 

[Suricate]

HI Peter,

Thanks for your reply, it does seem interesting and i am happy to hear that your experiment seems to be working. maybe i too should try somethig similar and see what happens.

Hey let me know how your closed system developes, i owuld like to stay in communication with you on this subject.

 

[Peter Lovett]

No trouble but its still some year away yet need to save up the money and it will be done in conjunction with an extension to the house. But yes i will keep you imformed.

Where are you in this little world

 

[Opcn]

you need lots of two things, diversity and light. I would suggest to you that you start out witha large tank, atleast 55 gallons, 200 would bebetter and into that put a layer of 3-4 inches of high quality dirt, no vermiclite and good humus content, some coarse sand would bee a plus IMHO. then ontop of this put a shallow layer of gravel to keep the mud from being stirred up, and put inyour liveplants and driftwood and a few caves would probably be good too. Seed with daphnia and go around and find other microcrustaceons, freshwater mysis shrimp might work, rotifers, cyclops, and amphipods, planaria (I'll bet you can find most of these in a local river pond or lake) you can also seed live tubiflew worms as well. Run this for a while to let the populations build up and stablise and possibly inject CO2 durring the day and after a month or so get a few small fish that will breed (I think dwarf cichlids are a great idea)and let em go.

Giid luck

 

[playfulalliecat]

Peter, I am a bit confused by what you mean when you say F1. Were your apistos F0? That is the only way you could be raising F1 as that refers to spawn from F0 or wild caught parents. Just curious as you really didn't mention that.

 

[Peter Lovett]

Peter, I am a bit confused by what you mean when you say F1. Were your apistos F0? That is the only way you could be raising F1 as that refers to spawn from F0 or wild caught parents. Just curious as you really didn't mention that.

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Sorry yes the fish where wild making this generation F1.

 

[Ed4567]

Go for a reef tank you know you want to....

 

[Peter Lovett]

My proposed pond will hold 2000 gallons. About 4" of silica sand and with peat filtered water. I would not add to much in the way of nutrients to the system you are asking for trouble. What you are looking to create is a ecosystem not a pretty picture. You need to choose plant that grow quick and use ammonia as there primary sort of nitrogen.

Filtration should be kept to a minimum less than one turn over an hour so that free floating algae is not removed from the system to quickly and food items like daphnia are also not removed. Also snails are very important and should be included into the system. One they consume other types of algae and encourage the growth of other micro organisms.
Also the system should not be cleaned too often and when it is it should not be cleaned too thoroughly as not to remove the fishes food souce.

 

[Opcn]

Also it should be airated, airation doesnt remove the algea or daphnia but the water current and O2 are useful (except durring the day, when CO2 might be stripped to quickly.)

 

[Peter Lovett]

Also it should be airated, airation doesnt remove the algea or daphnia but the water current and O2 are useful (except durring the day, when CO2 might be stripped to quickly.)

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There is no need for it have aeration but if you want to add it then thats fine. Under the population level that an aquarium/pond can hold oxygen levels will be fine and so will the CO2.

OPCN you seem to be worrying to much about the plants and not enough about the fish. Adding CO2 will make the plant grow and strip the tank of nutrients. Reducing the growth of the algae. Which is the fundamental part of whole system. Plant are only included as a method of filtration (To reduce nitrates and ammonia) and to give the small food item some where to hide so that the population is not completely wiped out.

I have been running my experiment for almost 2 years now. The fish are healthy the only differences that they show over the ones that i feed is that they spawn less often and that the fry grow slower. Which prolongs the brood care by a about a month.

Ed4567

No I don't think so.

 

[modernhamlet]

Sounds like a tough balance to keep. If there are light and nutrients, either plants or algae are going to expand to fill any and all gaps, Do you ever get algae blooms?

As a complete aside, my mbuna spend much of their day scraping algae off of the rocks in my 75g. It probably only makes for 20-30% of their food intake though. Cool to watch though...

 

[Peter Lovett]

I don't get algae blooms as. Because of the low nutrients the system things keep quite stable. I suffer more from die off of the plans. Which is okay as they rot they release the nutrients back inti the system. I think one day I should try and get an approximation on the over all bio mass.

Well your fish are doing what come naturally to them. Which is as you say great to watch.

 

[OohFeeshy]

Sounds interesting. In theory, it really isn't very hard to keep a self feeding tank. Or, I suppose, a self cleaning. I think theres 2 main things to consider- feeding and the nitrogen cycle. Both can be overcome with the use of many many plants and small aquatic life, such as daphnia. I'm not sure how they breed in captivity, and if they do, but it would be interesting to try it with a slightly lower water level, semi-aqautic plants that come out of the water, insects suck as mosquitos, microcrickets etc. and archer fish.

 

[Ed4567]

It is common in saltwater tanks to provide a 'refugium' above the main tank which does not contain predators and provides a place for 'pods etc. to breed. I appreciate this is rather taking away from the point of a complete ecosystem within one box; however it may be of use in much smaller tanks where predation could devistate fauna populations.