I also agree with the above statement, 3-1 female to male ratio is perfect. Right now i have 1-1 ratio(I'll be fixing that on payday) and the female is constantly harassed. It's good to give your females a break from a pesty male, especially if your expecting fry.
25gallon: 12 assorted neon tetras, 1 algae eater, 4 rosey barbs, 4 zebra danios, 1 white skirt tetra, and 2 guppies(1 male and 1 very pregnant female)