There are many types of fish tanks available today. They come in all shapes and sizes ranging from the standard rectangle to round with every geometric shape in between. The most common type construction is the all glass type, whose joints are sealed with clear silicon rubber, there are also available the new Euro style tanks where the clear silicon is replaced with black. Acrylic tanks are also becoming more commonplace.
Larger tanks are easier to care of.
The toxic substances released by the Biological or Nitrogen cycle are more dispersed in the larger volume of water, which allows the water quality stay higher for longer periods of time. Beginner hobbyist with their lack of experience will benefit from the larger tanks. For the beginner I would recommend the standard and inexpensive rectangular 55 gallon all glass aquarium with the approximate measurements of 48 inches long by 12 inches wide and 20 inches tall. A tank this size is easy to care for and yet not too large to be overwhelming. A common misconception of small fish equals small tank is not always true as the smaller fish tend to be more active and need more space to swim in.