Fish tanks are available in a wide variety of sizes, shapes and materials. Before you purchase your first aquarium it is important to consider how different designs will affect your fish.
In terms of the overall water capacity a larger tank will often be better. A bigger tank is normally recommended to beginners as it is much easier to maintain good water quality. The larger water volume enables more stability in the aquarium due to the dilution effect. In smaller aquariums waste products will be more concentrated and have a greater negative effect on water parameters.
When choosing an aquarium you should find out the number of fishes it can support before making your purchase. Overstocking a tank will cause problems for your fish and may result in death so if in doubt buy a bigger tank or keep less fishes. One common way that is often used to determine how many fish can be housed in an aquarium is the ‘one inch per gallon’ of water rule. This is calculated as the length of the fully grown adult fishes compared to the volume of water after displacement. Although this is ok to use as a general guide, it does not take into account many other factors such as gaseous exchange and filtration.
Aquariums can be built in almost any shape but the most common ones are rectangular, bow fronted and hexagon tanks. The shape of an aquarium can make the overall look very aesthetically pleasing if you get it right. However, you should also keep in mind that irregular shaped aquariums can often cause distortion when viewing your fishes.
The standard rectangular shaped aquarium has a length double the dimensions of its width and height. This traditional style aquarium remains popular and is suitable for most fish as it provides plenty of swimming space, a good surface area and a large front viewing panel. Tall column tanks have become fashionable as a space saving option but they do not provide enough horizontal swimming space to keep any more fishes than a tank half the height.
It is important not to only think of the design aspect of the tank. You should also take into consideration how the shape of the tank will affect the fish that you will be keeping. Some of the larger and more active species of fish will need plenty of swimming space so the tank should be long enough to provide enough room. Bottom-swimming fish such as Rays will need more space on the substrate and will appreciate a tank with a larger footprint. Other species such as Angelfish and Discus will prefer a taller tank. Coldwater fish generally require more oxygen than tropical freshwater species so the surface area of the aquarium should be large.
Tanks can be built from almost any material including concrete, wood, fiberglass, acrylic and glass. There are advantages and disadvantages to every material but the two most common in the trade are acrylic and glass. Your choice of material will be dependent on your own setup and the size and shape of the aquarium.