It may sound counter-intuitive but the larger the aquarium, the easier it is to look after. The reason for this is simple; the larger the body of water, the more dilute anything dissolved therein will be. This is particularly important when considering the harmful products of fish waste, such as ammonia and nitrite. These harmful substances can quickly accumulate in smaller aquariums, without adequate filtration. Now, although most people purchase adequate filtration alongside their first aquarium, that filtration system becomes obsolete when they begin to overload that aquarium with fish, as many first-time fish-keepers do. At that point, the well-meaning beginner is left with two options; purchase a larger aquarium or upgrade the filtration system. Most opt for the second option. The additional monetary expense of purchasing a new filter would have been better spent on purchasing a larger aquarium in the first place; as in larger aquariums, even with limited filtration, harmful substances can be diluted down to non-harmful levels before being removed by the filtration system. A larger aquarium will also prevent rapid nitrate accumulation. Although nitrate is non-toxic at lower levels, it begins to have an effect on the overall health of the fish as it accumulates. Therefore, when purchasing your first aquarium, go for the largest aquarium possible and you will be saved a whole lot of trouble in the long run.