Filters are an important part of any aquarium set-up, whether freshwater or saltwater. There are three main types of filters: mechanical, chemical and biological. Each type has a different purpose and all three are necessary for a healthy aquarium environment.
Mechanical filters remove physical debris from the water column such as uneaten food, fish waste and other particulate matter. Chemical filters help to remove dissolved organic compounds (DOCs) from the water which can contribute to water quality issues and affect the health of your fish. Biological filters provide a home for beneficial bacteria that break down ammonia and nitrites, two toxic byproducts of the nitrogen cycle.
While it is possible to have an aquarium without a filter, it is not recommended as it will be much more difficult to maintain water quality and your fish will be more susceptible to diseases. A well-functioning filtration system is one of the key components of a successful aquarium set-up.