do you have a tank currently or would you like us to suggest a good size tank for the fish you want to keep? I suggest getting the largest tank that will fit your area or that you can afford, which im guessing is no bigger than 30 if thats what you plan to upgrade to in a year. If price is a factor, get a used tank from classifieds or craiglist, but if space is the factor you can always get a larger tank thats tall rather than long.