The type and size of the aquarium depends on the space available, the cost, and the needs of the fish. Keep in mind, that larger tanks are easier to take care of than small tanks. The reason that large tanks ae less trouble because there is more water volume for environment. For instance, the temperature of a 10 gallon tank can be affected more rapidly by sunlight or a cold night than a 55 gallon tank. A 55 gallon tank tends to have a much more stable pH than a 10 gallon tank. Therefore, beginning aquariasts should choose as large a tank that they can accomodate, economically and space-wise.

Choosing the Tank Location: The first requirement for the location of a fish tank is in an area that can support its weight. Water is very heavy, about 8 lbs a gallon (about 1k/l). For example, a 20 gallon tank weighs more than 160 punds not including gravel or rocks. Once a place that can support such a weight is found, check that the location fills other requirements. The tank should be away from direct sunlight, which will encourage algal growth and can affect the water temperature. Avoid placing the tank near a window or door where drafts may cool the tank. Similarly, the tank should be near electrical outlets and in a location where water changes can be easily made.

Cost: Unfortunately, cost is usually an important factor in selecting he type and size of tank one can afford. generally glass tanks are less expensive than plexiglass tanks. Usually the smaller the tank, the less the price (except for those under 10 gallons). The least expensive tanks are usually those that are mass produced, such as 10, 20 and 55 gallon tanks.

Fish Needs: Before selecting a tank, the type and number of fish should be considered. Take into account the size of tank that the species requires. For example, an Arowana or oscar cannot be expected to survive in a 10 gallon tank. Although it is not essential to decide what fish you are planning to have before buying the tank, for best results, decide beforehand.

The most common types of material used for tanks in the United States are glass and plexiglass. Both of these materials appear to work well for keeping aquarium fish.

Glass tanks are advantageous because they are widely available at a relativity low cost. Glass tanks, made by reputable manufacturers, are generally reliable as far as not leaking. However, some cheaply manufactured tanks are subject to leakage and breakage. Be sure the tank you buy is guaranteed against leakage for a period of time. All glass tanks are heavy.

Plexiglass tanks are gaining popularity in the United States. These tanks are light, attractive, and are available in a variety of sizes and shapes. plexiglass tanks are less likely to leak than glass tanks. there are few drawbacks including a higher cost than glass tanks and a vulnerability to scratches. Some report that large tanks may "bow" with time.

There are other tanks available, but they are not nearly as common as the two mentioned types.

Whatever tank is chosen, be sure that a cover is included. The cover will reduce evaporation and lessen the chances of a fish jumping out.

Aquariums are available in a number of shapes, the most common being rectangular. rectangular aquariums are good for housing fish because they usually have a large surface area for gas exchange. However, so-called "tall" tanks which have little surface area are less suitable and strong aeration is required. Generally, tall tanks cannot support as large a fish load as shallower tanks.

Tanks with other shapes, such as hexagon, cannot support as many fish as a rectangular aquarium, again because of the smaller surface area. Hexagon do not allow as much long, open, swimming room.