I have a 40 gallon directly under a south facing window. It has a back wall of emergent plants (Calla lilies, pitcher plants, peace lilies, Bacopa, begonias and snake plants) so no algae issues. It runs on air driven sponge filters, and has a self sustaining community of Chromaphyosemion poliaki killifish. If I wanted to convert it to the set up you want, it would involve two minor changes. First, I'd catch and remove the poliaki. Then I'd go out back and scoop out the live foods I feed several times a week, and put them in. In tanks with fish, they get eaten. In a fishless tank with good light (for the micro-organisms they eat), they'd do well.
If I let the poliaki eggs that are always being laid hatch, it would still work as long as I removed the juveniles when they got to one inch. Production would end with that, so I could add a pair of 1.5 inch small fish, and still have the critter tank. To run a tank with micro-life large enough for us to see it, we need very few micro-fish. It's like the old kids' cartoon, the Magic Schoolbus. You have to get down to the sizes of the creatures in it, and fish have to be small.
My one tank where I accidentally achieved a daphnia colony had a killifish that reaches under 2 inches max, with a slender body and an easy going appetite. Their numbers were really low.
Scuds have settled into tanks here before because many fish won't eat them. But as far as a pond community goes, they're one element. Even with an undergravel, a lot of the creatures you want aren't substrate dwellers.
I wish it would work, but if wishes were fishes...
If I let the poliaki eggs that are always being laid hatch, it would still work as long as I removed the juveniles when they got to one inch. Production would end with that, so I could add a pair of 1.5 inch small fish, and still have the critter tank. To run a tank with micro-life large enough for us to see it, we need very few micro-fish. It's like the old kids' cartoon, the Magic Schoolbus. You have to get down to the sizes of the creatures in it, and fish have to be small.
My one tank where I accidentally achieved a daphnia colony had a killifish that reaches under 2 inches max, with a slender body and an easy going appetite. Their numbers were really low.
Scuds have settled into tanks here before because many fish won't eat them. But as far as a pond community goes, they're one element. Even with an undergravel, a lot of the creatures you want aren't substrate dwellers.
I wish it would work, but if wishes were fishes...
