I have never bred rosie reds but I agree that trying to breed enough guppies to feed a tank full of fish is not cost effective, they are much cheaper just to buy.
I don't know about the weather down in Atlantis but in many parts of the surface world an old claw foot tub full of floating plants and elodea works as a nice decoration for your garden or porch and will produce enough guppies or gambusia to make nice snacks for your piranhas and doesn't take much effort.
I don't know about the weather down in Atlantis but in many parts of the surface world an old claw foot tub full of floating plants and elodea works as a nice decoration for your garden or porch and will produce enough guppies or gambusia to make nice snacks for your piranhas and doesn't take much effort.