fish that survive off the aquarium…

[Magnum Man34 148]

I have several odd varieties of hillstream’s that I never see at feeding time, and like many small fry, must be grazing the tank… I see these hillstream’s often enough, and for long enough, that they must be surviving off the tank… I try not to over feed, that there is just feed laying around all day n the tank… I’m guessing if anything micro amounts, but not enough to sustain them alone

many types of fry of fish not specifically algae eaters seem to find something to eat, after their yolk sack is gone…

this brings up the thought of an aquarium that requires no feeding, optimized for producing a food chain, and not stocked so heavily, that it doesn’t exceed what the tank is capable of producing … of coarse if we wanted to graduate to 1 larger predator fish, we would likely need to have a tank much larger than most could handle, but thinking on a micro level even, it would be an interesting tank… I’ve just never had a tank the micro foods like copods, for example, have gone wild…

thoughts???

 

[GaryE]

I've seen people who said they had it set up. It's a common fantasy. Maybe a huge tank with a tiny number of biofilm eaters would manage it, but most of the time, people deceive themselves to feel good about neglecting their pets with such a deal.

I've had daphnia, cyclops and other beasts establish themselves in killie tanks, but only if I continued feeding well and had small numbers in large, heavily planted tanks. Give me a life in a tropical country with long, low tanks exposed to the elements, and it would work.

Tanks aren't natural. They're too small, and rooms aren't forests or savannahs. A lot of the life in a stream comes from outside the water - insects falling from the canopy, laying eggs or living an aquatic larval stage, leaves and fruit, etc. A stream extends outwards and draws inwards. If the room your tanks are in is that wild, good luck!

We can have healthy tanks as natural as circumstances allow, but we have to provide the out of water foods. When spiders build webs close to the surface of the tanks in my garage, I leave them be. The spiders get picked off by fish no Canadian spider is prepared for. But when I swept my net in any African stream, if I so much as touched the streambank vegetation, the net was full of tiny spiders. If any aquarist wants that in just above their tanks, go for it and tell us about the results...

 

[Rusty_Shackleford33 148]

If any aquarist wants that in just above their tanks, go for it and tell us about the results

Well no aquarist besides me.

I agree 100% There is only so much nature we can try and replicate within our glass boxes, and a self sustaining food chain is not one of them.

 

[Uberhoust]

I think it can be done for a short time but as Gary has mentioned our tanks are closed systems which can never match the conditions of a natural environment. When fish deplete a resource in the natural environment, they can move to another environment, if they cannot move they adapt to a different resource, and if they cannot move or adapt they die. The dying aspect is what I expect if we try to maintain a full ecosystem within an aquarium to its final end, but for outside ponds we can go a little further because there is more food available, but you still have to do some maintenance (I have a pond with lots plants and fathead minnows, that only gets cleaned from time to time, that has existed for many years now)

 

[Magnum Man34 148]

BTW… not specifically talking about a no work tank… still doing water changes etc. ( in fact I suspect much extra work would be needed to sustain this type of tank )

just either keeping fish, that won’t take food from us, or maintaining a tank, with enough micro fauna, and a low enough number ( perhaps a pair ) of fish that eat that micro fauna… and since I’m not a good raiser of micro fauna, perhaps having a tank that meets their conditions, and adding a jar full every once in a while… lots of plants and places for food organisms to thrive and hide, but in numbers that would support some predication…

my thoughts are a hillstream type tank, trying to get the tank to maintain aufwucks, rather than our normal “sterile” normal aquarium algae

 

[GaryE]

The thing is, you'd need organisms in the aufwuchs, as in nature. And that would deplete. A 6 foot, 120 gallon with intense lighting, maybe, if you had two 3 inch fish in it...