I don't care too much about the guppies in the 15G, the betta is my new project for this tank. Guppies will eventually go in the 55G with the Oscar if they become a problem. I'd like to breed the betta, should I put a female in there only when he has built a bubble nest? Can I raise the betta's fry in that tank? As for the 20G, that's where I want the pretty guppies, I'm trying to breed the four points male with the black female, can't wait to see what all those babies will look like once adult. How about the corys? Does anyone think I could breed them in the 20G?
P.S. All the plants in those tank are really low maintenance and easy to grow.