#1- A freshwater aquarium is a better choice for beginners than a saltwater aquarium.
While the average freshwater setup is probably slightly less challenging to maintain than the average saltwater setup, many freshwater tanks are very complicated, some even more so than a simple saltwater tank. Basically, you can pretty much make your tank as simple or complicated as you want to, and therefore the type of tank you choose need only be determined by what most appeals to you.
#2- Clownfish are very difficult to keep in captivity.
Many people have the mistaken idea that clownfish are very challenging fish, only suitable for the most advanced of hobbyists. This is completely untrue. This myth may have its basis in the fact that anemones are quite difficult to maintain in captivity. However, contrary to popular belief, clownfish do not need an anemone to survive. Under the right conditions, they will flourish in captivity without the presence of an anemone.
#3- You need to be a chemist to understand the complexities of the filtration of a tank.
While it's true that maintaining a thriving saltwater tank takes a little head knowledge, any person with the right amount of dedication and a willingness to learn can understand enough about tank filtration to be successful.