What are the main types of aquarium filters?
Written by
Susan Taylor
Reviewed by
Prof. David Walsh, Ph.D.The selection of the right aquarium filter is vital and strongly influences not only water clarity but also the health of your fish. Filters clean the water, supply oxygen and eliminate toxins. There are five basic types of filters, each with its own advantages and limitations. This article investigates these types: sponge, HOB, canister, internal and undergravel systems to help you to select your aquarium filter more intelligently.
Sponge Filters
- Provide gentle biological filtration ideal for fry and shrimp
- Require air pumps to operate creating fine bubble streams
- Clean monthly by squeezing sponges in tank water
- Best for tanks under 20 gallons
HOB Filters
- Offer combined mechanical and biological filtration
- Hang on tank rim with water return creating surface agitation
- Replace cartridges monthly rinse media biweekly
- Ideal for 20-50 gallon community tanks
Canister Filters
- Deliver powerful multi-stage filtration for large volumes
- Position below tank with intake/outflow tubes
- Maintain quarterly clean mechanical media monthly
- Essential for tanks over 50 gallons with heavy bioloads
Internal Filters
- Submersible units with compact space-saving designs
- Suitable for nano tanks under 10 gallons
- Clean weekly due to rapid clogging from debris
- Perfect for betta tanks and hospital setups
Undergravel Filters
- Use gravel bed as biological filtration medium
- Require frequent vacuuming to prevent toxic gas buildup
- Best suited for simple fish-only setups
- Largely outdated by modern filter technologies
Ensure that the choice of filters suits the needs of your aquarium. Space restrictions for the population and maintenance possibilities should also be considered. Small tanks typically require sponge filters, while larger systems can utilize canister-type filters effectively. The flow object and oxygenation needs of the fish species should be satisfied whenever necessary.
Regular upkeep is necessary, no matter what types of media are used. Mechanical media should be cleaned weekly to avoid clogging. Biological media can be preserved by rinsing in tank water, and chemical media should be replaced monthly to prevent the release of pollutants into the environment. With this regular maintenance, optimum water quality and healthy fish are ensured.
Understand the advantages and disadvantages of every filter before making a selection. The less complicated sponge and HOB (hang-on-back) filters are better suited for beginners. More sophisticated canister systems allow for greater control by the expert. Avoid using an undergravel filter on a planted tank. The best choice is the one that fosters the type of aquatic habitat most consistent with your desired level of commitment.
Read the full article: Aquarium Filter Types: Your Essential Guide
