Have a close look at your water Mark. If you want to keep common mollies, it is best to have hard water with a high pH. If you have soft water, you might want to go with fish like neons instead of typical livebearers. Another option that you will seldom see mentioned in an American forum is killies. They are delightful small fish related to the livebearers but often are more colorful. Some of them are good community fish while others are not, just like the rest of the fish that I have seen mentioned here.