There are two types of freshwater aquariums: tropical and cold water.
Tropical freshwater systems are the most recommended systems for beginners.
This is because the majority of fish retail stores, stock an abundance of tropical plants and fish.
It also gives you the most options, allowing you to tailor your fish tank to your personality.
Tropical Freshwater Fish - are the most inexpensive and easiest to maintain.
This is why most fish store sales people will recommend this type of fish tank system for a beginning hobbyist.
The 3 most popular species of tropical freshwater fish are:

• Platys - this fish offers hours of viewing entertainment, it is colorful, active, and very curious.
  
• Guppies - a peaceful fish and perfect for hobbyist that want to try breeding fish.
  
• Tetras - are brightly colored fish that are easy to keep in captivity.
  

Tropical Freshwater Systems - allow you to set up a colony in your aquarium, consisting of a variety of species.
Most freshwater fish can exist side-by-side peacefully.
You can also decide to keep more aggressive fish, such as bettas or cichlids.
Tropical Aquarium Kits - instead of buying all of the equipment yourself you can buy a tropical aquarium in kit form.
This takes the hassle out of purchasing all the components that you need to make up a system.
These kits include the basics that you need to get started: a tank, net, hood, filter, food, instructions, and the heater required for a tropical tank.
The kit does not contain the extra decorations that you may want to add to the fish tank.
If you would like to create a more esthetically pleasing tank you will want to purchase some gravel, plants, or decorations.