A 10 or 20-gallon aquarium may be ideal for beginners.
The tank should not be placed in direct sunlight since this can adversely affect the temperature of the tank.
All aquariums should have a cover to prevent evaporation of water and to keep those leaping fish in the tank.
Aquariums may be made of glass or acrylic. Look it over carefully for scratches or cracks before purchasing.
A tank needs a filter to keep the water clean, a heater if you are planning to keep tropical fish and then one has to decide on the decorations such as the kind of gravel, the type of plants whether live or artificial and other decorations such as natural rock, driftwood and so on.
Decorations enhance the look of your aquarium. When setting up the tank, it is important to read all the instructions that come with the filter, the heater, size, temperature, decorations and so on.
A fresh water tank is easier to manage for beginners than a salt water or marine tank. Use clean tap water to fill your aquarium. Let the water stand for several days so that the chemicals in it such as chlorine and ammonia, harmful to the fish get time to evaporate. 10 or 20 gallon of water could support your requirements.
Different types of filters are available to help keep the water in the aquarium clean from the waste excreted by the fish. They are 'under gravel' filters, box filters and outside filters. The more filter material a filter has the better filter it will be.