Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
2. You cannot add that many, the tank would be over stocked.
3. They are known to, but see below.
4. They might. If Guppies laid eggs. Gups are live bearers.
Full answer to the concept:
You are describing 'The perpetual motion fur farm'. It cannot work.
Here is the 'perpetual motion fur farm':
Feed rats to cats.
Kill the cats to get the fur, and feed the bodies to the rats.
Raise a few litters of rats to feed the cats.
Remember the basic food chain:
The prey will only support 1/10 as many predators as there are prey (based on weight).
It takes 10,000 pounds of grass to feed 1,000 pounds of rabbits. It takes 1,000 pounds of rabbits to feed 100 pounds of wolf.
Translate this to fish:
Feed the guppies one hundred grams of fish food.
This will support 10 grams of guppies.
This will support 1 gram of Gouramis.
Remember that the mother Guppies burn up a lot of energy being pregnant, and a certain amount of the food they eat gets turned into baby guppy.
If all they had to eat was baby guppies from other litters, they could not make more babies than they are eating. They could only make 1/10 as many (or less- they need energy to keep themselves alive, too). So if one mother Guppy ate 10 litters, she could produce 1 litter (or less).
Good idea to raise live food to feed your fish.
Set up a couple of 'food stations' equipped to keep the 'prey' alive.
Salt water tank to raise brine shrimp, some dishes of oat meal or whatever for certain worms, a box of kitchen compost for other worms, a green water aquarium for daphnia and so on.
People do keep a tank of live bearers to feed to their predatory fish. It is a lot healthier than buying poorly raised feeders.
If you are interested in raising these other animals, then the work may be worth it. Or, if you have a lot of tanks. But to raise enough food, and varied enough food for a balanced diet it is not worth it for just one aquarium.