When selecting your aquarium, the size and quality are important factors. A better type aquarium is cheaper in the long run, as it is to be your fishes’ home for a long time. Sizes range from less than one to hundreds of gallons. Since a 1-gallon tank holds only 5 fishes at the most, a 10-gallon is considered the most appropriate size for the beginner, for it ‘will comfortably hold 10 pair of average size fish.