Does your 20-gallon fish tank look a little cloudy lately, even after a water change? Keeping aquarium water crystal clear and healthy for your fish can feel like a constant battle. Choosing the right filter for a 20-gallon setup is tricky. Too weak, and you get a murky mess. Too strong, and your small fish might feel like they are swimming in a washing machine! Many aquarium owners worry about finding that perfect balance between powerful cleaning and gentle flow for their smaller tanks.
Don’t let filter confusion stress you out! This guide cuts through the noise. We will explore the best filter types specifically designed for 20-gallon aquariums. You will learn exactly what features matter most, from biological filtration to flow rate. By the end of this post, you will confidently select a filter that keeps your fish happy and your water sparkling. Ready to upgrade your tank’s health? Let’s dive into the best filtration options for your 20-gallon home!
Top Fish Tank Filter For 20 Gallon Tank Recommendations
- LED indicator light flashes when water cannot pass through the cartridge, generally indicating it's time to change the cartridge
- Self-priming filter pump will auto-start initially or restart if power is interrupted and restored
- Provides mechanical, chemical, biological and optional, additional specialty pad filtration
- High flow rates for optimal dissolved oxygen content to promote healthier, more active fish
- Internal pump design helps dampen noise and eliminate leaks with self-priming feature
- PERFORMANCE - This aquarium filter offers a powerful 130GPH flow rate, 2.5ft maximum head height, and 3.5W power, suitable for 10-40 Gallon tanks.
- SATETY MOTOR - This internal aquarium filter has an fully epoxy-sealed motor, tested with super high voltage during manufacturing to avoid electricity leakage.
- TRUE 4-STAGE FILTRATION - Featuring 3 sponge blocks and bio-balls for true 4-stage filtration, including COARSE SPONGE to capture large impurities, FINE SPONGE to catch small particles, Bio-balls for cultivation of beneficial bac-te-ria for the environment in the aquarium, and CARBONIZED SPONGE to absorb odors and chlorine.
- AERATION - The fish tank filter comes with accessories to increase oxygen supply. It's important to note that for optimal aeration, this fish filter should not be positioned too deep in the water and the air regulator should be positioned higher than the water level.
- TIPS - For tanks over 40 gallons, use 2 filters placed at the back corners for complete filtration and improved water circulation.
- INCLUDES CARTRIDGE: The molded ribbed back maximizes contact with water – includes premium activated carbon.
- BIOLOGICAL FILTRATION: Bio-Foam biological filtration removes toxic ammonia and nitrites on contact.
- QUIET: Decoupled motor with dampeners reduces noise to below 40 dB.
- POWERFUL: Impeller and motor assembly designed for efficient power usage filters 10- to 20-gallon aquariums 5 times per hour.
- SLEEK DESIGN: Designed to fit standard aquarium hoods and canopies, the Aqua-Tech Ultra Quiet Power Filter makes aquatic filtration easy.
- CRYSTAL CLEAR WATER – Unlike other fish tank filters on the market, the Atlantis Aqua submersible aquarium filter draws water through the bottom of the filter, rather than the sides. This means the water travels through the full fish filters system rather than taking the easiest path and being partially filtered, like other fish filters.
- NO NEED TO CHANGE FILTER PADS – The filter sponges last a lifetime, so no need for expensive monthly replacements! Can be used as a Turtle Filter. Detachable sections so it can be used as a fish tank filters 20 gallon - 55 gallons and can be used in a goldfish, tropical or saltwater tank.
- HEALTHIER FISH – The internal aquarium filter oxygenates the water which is vital to the health of your pets - they also enjoy swimming in the waves!
- ALL-IN-ONE FILTRATION SYSTEM – Our aquarium filter includes a sponge filter and a biological filter. The filter is 11.4" tall and 2.75" wide but it can be used with one section removed and is 7.6" tall.
- MANCHESTER BASED DESIGNER – We are a Manchester based company that is passionate about providing high quality products whilst offering the best customer service. All of our products come with a 1-year warranty. This filter is not suitable for small shrimp or small fish.
- Fine Sponge Filtration: Provide mechanical and biological filtration and trap debris or wastes without sucking up shrimp or fry. Keep fish tanks crystal clear and healthy.
- 80 GPH Water Pump: 2 types of water outlets (drenching pipe & spraying pipe). Slide the knob to freely adjust water flow as needed. Greatly promote water circulation to keep water fresh.
- For 10 Gal Tanks: Size: 1.6" W x 5.3" H; Power: 4 W. Fit for 10-20 gallon small fish tanks. Suitable for the breeding and feeding of various ornamental fish, shrimp or fry.
- Oxygen Supplement: Equipped with clear airline tubing for easy air entry. Produce numerous bubbles – a great way to increase oxygen solubility in the water and enliven the aquatic lives.
- Easy to Clean: Separate the pump from the filter, remove the impeller cover and clean the pump thoroughly. Remove the bottom cover to take out the sponge. Rinse the sponge every 2 weeks – only wash it with aquarium water!
- INCLUDES CARTRIDGE: The molded ribbed back maximizes contact with water – includes premium activated carbon.
- BIOLOGICAL FILTRATION: Bio-Foam biological filtration removes toxic ammonia and nitrites on contact.
- QUIET: Decoupled motor with dampeners reduces noise to below 40 dB.
- POWERFUL: Impeller and motor assembly designed for efficient power usage filters 20-to 40-gallon aquariums 5 times per hour.
- SLEEK DESIGN: Designed to fit standard aquarium hoods and canopies, the Aqua-Tech Ultra Quiet Power Filter makes aquatic filtration easy.
- Efficient & Quick Filtration: Equipped with a powerful motor and 360° large area bio filter sponge, our aquarium internal filter effectively removes impurities, debris, and harmful substances, ensuring crystal clear water.
- Powerful Water Circulation: The included 320 GPH filtration pump delivers strong water circulation and oxygenation, promoting a healthy ecosystem for your fish and aquatic plants. Suit 20-50 gallon tanks.
- Easy Installation: Quick and simple setup with included powerful suction cups and instructions. Easy to remove the sponge for cleaning or replacing other filter media.
- Space-Saving Design: The compact and sleek design of our fish tank filter maximizes the available swimming space for your fish while providing efficient filtration, ensuring both beauty and functionality.
- Quiet Operation: Say goodbye to noisy filtration systems. Our aquarium filter operates silently, ensuring a tranquil and stress-free environment for both you and your aquatic companions.
- PLUG-AND-PLAY - The AQQA aquarium filter is designed for ultimate ease of use. Unlike many traditional filters that require water to be added before starting, our fish tank filter can be powered on directly—no need to fill with water! Simply plug it in, and the filter will start working immediately, making setup quick and hassle-free. Suitable for fish tank with a thickness of up to 1.2 inches (28mm). (Note: When in use, the water pump should be below the water surface)
- CUSTOMIZABLE WATER FLOW - Our filter for fish tank features an adjustable flow control system, allowing you to effortlessly fine-tune the water flow to match the needs of your tank's inhabitants. Whether you have delicate fish that prefer calm waters or species that thrive in stronger currents, our aquarium filter offers the flexibility to create the perfect environment
- TRIPLE BIO SPONGES FOR EFFICIENT FILTRATION - Our fish tank filter provides superior filtration to maintain a pristine and healthy aquarium environment. Its innovative design, featuring triple bio sponges, contains activated carbon, ensures both mechanical and biological filtration. This allows the filter to effectively trap debris and waste, helping to keep the water clean and clear
- ULTRA QUIET OPERATION - One of the standout features of our fish filters for aquariums is its ultra-quiet operation. Designed with advanced noise reduction technology, this small aquarium filter runs at a barely audible level, making it perfect for bedrooms, offices, or any space where noise is a concern. With noise levels kept below 30 dB, you can enjoy a peaceful environment without disturbing either your aquatic pets or your household
- SPACE-SAVING & ULTRA-THIN - This silent fish tank filter is compact, efficient, and ultra-thin, designed to save valuable space in your aquarium setup. Its Hang-On-Back (HOB) installation method offers a convenient solution for tanks from 20 to 30 gallons. The sleek design blends seamlessly with your tank’s appearance, delivering high performance without being intrusive
The Ultimate Buying Guide for Your 20-Gallon Fish Tank Filter
Choosing the right filter is vital for a healthy aquarium. A good filter keeps your water clean and your fish happy. This guide helps you pick the best filter for your 20-gallon tank.
Key Features to Look For
When shopping, focus on these important features. They make a big difference in filter performance.
- GPH Rating (Gallons Per Hour): This tells you how much water the filter cleans every hour. For a 20-gallon tank, you want a filter rated for at least 80 GPH. Better yet, look for one rated for 100-120 GPH. This ensures excellent cleaning power.
- Filtration Types: Good filters use three types of cleaning: mechanical, chemical, and biological.
- *Mechanical* traps visible dirt, like food bits.
- *Chemical* uses carbon to remove odors and discoloration.
- *Biological* hosts good bacteria that break down harmful waste.
- Filter Media Accessibility: Can you easily change the filter cartridges or sponges? Easy access means you clean the tank faster.
- Noise Level: Some filters hum or bubble loudly. Look for descriptions like “whisper quiet” if your tank is in a bedroom or living area.
Important Materials in Filter Construction
The materials used affect how long the filter lasts and how well it works.
Most quality filters use durable, non-toxic plastics. Make sure the casing feels sturdy, not flimsy. The motor inside needs to be reliable. Look for brands known for long-lasting pumps. The filter media itself matters greatly. Sponges should be dense enough to catch debris but porous enough for water to flow easily. Carbon should be high quality to absorb impurities effectively.
Factors That Improve or Reduce Filter Quality
What makes a filter great or just okay? It often comes down to the design and maintenance ease.
Factors That Improve Quality:
- Over-filtration: Using a filter rated slightly higher than your tank size (e.g., a 30-gallon filter on a 20-gallon tank) provides cleaner water.
- Layered Media: Filters offering separate sections for sponges, carbon, and bio-media work better than all-in-one cartridges.
- Adjustable Flow: Some filters let you turn the water flow up or down. This helps if you have sensitive fish that dislike strong currents.
Factors That Reduce Quality:
- Bypassing Water: If the filter design allows water to flow around the media instead of through it, the water stays dirty. Check user reviews for complaints about this.
- Cheap Carbon: Low-grade carbon wears out fast and stops cleaning smells quickly.
- Hard-to-Find Parts: If the manufacturer stops making the specific cartridges for your model, you must replace the whole filter unit later.
User Experience and Use Cases
Think about where your tank lives and what fish you keep.
If you keep messy fish like Cichlids or Goldfish, you need strong mechanical filtration and frequent cleaning. A Hang-On-Back (HOB) filter is a popular choice for 20-gallon tanks. They hang on the back rim and are easy to set up.
For planted tanks, you might prefer a sponge filter or a smaller internal filter. These usually create less strong surface agitation, which keeps CO2 in the water better for plants. Always check how easy the filter is to clean. If it takes an hour to take apart and reassemble, you might skip cleanings, which hurts your fish.
10 Frequently Asked Questions (FAQ) About 20-Gallon Tank Filters
Q: What type of filter works best for a 20-gallon tank?
A: Hang-On-Back (HOB) filters are often the best choice. They offer good flow and multiple media options for a 20-gallon setup.
Q: How often should I clean my 20-gallon filter?
A: You should rinse the mechanical sponges or cartridges every 1 to 2 weeks. Replace the chemical carbon media monthly.
Q: Can I use a filter made for a 10-gallon tank on my 20-gallon tank?
A: No, you should not. A filter made for a 10-gallon tank will not clean the water effectively for 20 gallons. You risk high ammonia and nitrite levels.
Q: Do I need to replace the biological filter media?
A: You should never replace all the biological media at once. This media holds the good bacteria. Only replace it if it physically breaks apart, and replace only a small part at a time.
Q: What does GPH stand for?
A: GPH stands for Gallons Per Hour. It measures how fast the filter moves water through its cleaning system.
Q: Are internal filters quiet?
A: Yes, internal filters (which sit completely underwater) are generally very quiet because they do not create surface splashing noises.
Q: Does the filter need to run 24/7?
A: Absolutely. The filter must run constantly, day and night. If the filter stops, the biological bacteria die, and toxic waste builds up quickly.
Q: How do I stop my filter from sucking up small fish or shrimp?
A: You can place a piece of fine filter floss or specialized pre-filter sponge around the intake tube. This stops small creatures from getting pulled in.
Q: What is the difference between chemical and biological filtration?
A: Chemical filtration (like carbon) removes dissolved impurities, smells, and colors. Biological filtration uses bacteria to convert toxic fish waste (ammonia) into less harmful substances.
Q: Should I clean my filter media with tap water?
A: Never clean your filter media with plain tap water. Chlorine in tap water kills the beneficial bacteria. Always use old tank water that you removed during a water change.