flikkitty11: You are severely overstocked, you might not have problems now, but you will at some point. 4.5 gallon is 4. 5 inch of fish. Roughly 10 cm of fish. Remember when they are bought they are usually babies and will still grow.

Personally I would only keep a betta in that tank.

jason_yyl: Same goes for you, you should not try and breed guppies in a tank that size, it will go out hand quickly. A male betta would be great for your tank.

Sorry if it is not really what you want to hear, but really it's about whats best for the fish, the guys at petstores will sell you anything, so don't trust them, research, research and then some more research.