The first decision a new aquarium owner needs to make is what tank to buy. Beginners are often tempted to buy a small aquarium first in order to get started. Buying a small tank is not recommended for beginners. The smaller the tank is, the harder it is to keep it clean and stable.
Of course, the consideration you need to think of first is where you are going to put your aquarium, and if you have space for the size of aquarium you want.
The reason that a larger tank is better for a beginner has to do with waste breakdown and oxygen exchange in water. The more water there is in a tank, the more the waste is able to break down naturally. Also, the more surface area of the water, the more oxygen is able to exchange, because oxygen is exchanged at the surface of the water. Another problem that beginners often face is the temptation to over-fill their tanks. A good rule of thumb is to get one inch of fish per gallon of water. Keep in mind the size your fish will be when they are full grown. So, with this rule, you can only keep two or three fish in a two-and-a-half gallon tank. Overcrowding a tank will cause there to be too much waste in the water, and your fish will not be healthy. So the bigger the aquarium, the healthier your fish will mist likely be. A twenty gallon tank is a great tank for the beginner. It is not too big to be overwhelming, but it is large enough to be relatively easy to care for.
Another factor to consider is the shape of the aquarium. A tall, thin aquarium will not hold as many fish as a short aquarium with the same water capacity, because the surface area of the water will be smaller. Also, a tall, deep aquarium will be harder to clean than a wide, shorter one. These unique shaped aquariums are very attractive, just keep in mind that they cannot hold as many fish as the shorter ones.
Additionally, you need to consider the weight of the filled aquarium and the strength of the floor beneath it. A gallon of water weighs approximately eight pounds. Do not forget to factor in the weight of the rocks and decorations you will be adding. Make sure whatever stand or shelf you are going to use to hold your aquarium can hold the weight of the final product. The most common sizes on the market are between ten and thirty gallons. Try to buy the largest tank you can afford. This will keep your creativity from being limited as you build your underwater world!