Imagine watching your beautiful fish swim in crystal-clear water. Now, picture that same tank clouded with murky film or smelling faintly of ammonia. Sound familiar? Choosing the perfect filter for your 20-gallon fish tank is one of the most crucial steps in keeping your aquatic friends happy and healthy. It’s not just about making the water look nice; it’s about life support!
The sheer number of filter types—hang-on-back, internal, canister—can quickly turn a simple purchase into a confusing chore. You worry about flow rate, filtration capacity, and noise levels. Getting it wrong means dealing with constant maintenance headaches or, worse, sick fish. We know you want reliable performance without breaking the bank.
This guide cuts through the confusion. We break down the best filter options specifically suited for a 20-gallon setup. You will learn exactly what features matter most and how to match a filter to your tank’s inhabitants. Get ready to stop guessing and start selecting with confidence! Let’s dive into the details of finding your perfect filtration solution.
Top Filter For A 20 Gallon Fish Tank Recommendations
- 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.
- 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.
- Dense floss removes particles and debris
- Activated carbon removes toxins, odors and discoloration
- Patented bio-holster removes toxic ammonia and nitrites
- Diffuser grid removes additional toxins while adding oxygen for more active fish
- Reduces splashing making the return exceptionally quiet
- UNIVERSAL DESIGN: Tetra Whisper 40i Internal Filter is an all-in-one air pump and water filter system.
- INTERNAL FILTER: Mounts on the inside of your aquarium with clip (included).
- CATCHES DEBRIS: Dense, dual-sided mesh filters debris and fish waste.
- AERATES WATER: Air-driven design filters up to 170 GPH while oxygenating water.
- CONVENIENT DESIGN: Uses large easy to change Bio-Bag cartridges; filter mounts inside aquarium, making it possible to place tank flush against the wall.
- 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
- QUIET AQUARIUM FILTER: The Tetra Whisper IQ Power Filter with Stay Clean technology contains a sound shield for quiet filtration less than 40 dB.
- SELF PRIMING: Submerged motor starts up with no priming required.
- CAPACITY: The Tetra Whisper IQ 45 Power Filter works in filters up to 45 gallons (215 GPH).
- STAY CLEAN TECHNOLOGY: By maintaining healthy pH levels, creates easier maintenance for healthier fish.
- CARTRIDGE REFILLS: Change cartridges monthly; uses large-sized Tetra Whisper Bio-Bag Filter Cartridges (refills sold separately).
- 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!
Choosing the Right Filter for Your 20-Gallon Fish Tank: A Buyer’s Guide
Keeping a 20-gallon fish tank clean and healthy is super important for your fish. The filter is the heart of your aquarium setup. It cleans the water so your fish can thrive. This guide helps you pick the best filter.
Key Features to Look For
When you shop for a filter, look closely at what it offers. These features make a big difference in how well your tank stays clean.
- **Flow Rate (GPH):** This means Gallons Per Hour. The filter must move water quickly. For a 20-gallon tank, aim for a filter that moves at least 60 to 100 GPH. A higher rate means cleaner water, especially if you have lots of fish.
- **Filtration Types:** Good filters use three types of cleaning: mechanical, chemical, and biological.
- *Mechanical* removes big bits like food and waste.
- *Chemical* uses activated carbon to remove smells and colors.
- *Biological* uses sponges or ceramic rings where good bacteria grow to eat harmful toxins.
- **Size and Fit:** Make sure the filter physically fits inside or hangs nicely on your 20-gallon tank without taking up too much room.
- **Noise Level:** Some filters hum loudly. If your tank is in a quiet room, choose a model known for being quiet.
Important Materials in Your Filter
The materials inside the filter determine its cleaning power and how long it lasts.
Most filters use plastic casings, which are durable. Inside, the sponges and pads should be made of high-quality, non-toxic foam. Chemical filtration almost always relies on **activated carbon**. This material is porous, meaning it has tiny holes that trap impurities. For biological filtration, look for media like ceramic rings or bio-balls. These materials offer a large surface area for beneficial bacteria to colonize.
Factors That Improve or Reduce Quality
Good filters last longer and clean better. Poor quality parts can fail quickly or even harm your fish.
What makes a filter better? A filter with easy-to-replace media cartridges improves quality. Filters that allow you to customize the media (meaning you can add extra biological material) are superior. Also, filters with adjustable flow rates let you control the water movement, which is great if you have small or sensitive fish.
What reduces quality? Cheap plastic that cracks easily is a problem. If the motor is weak, the GPH will drop quickly. Filters that only use one type of cleaning (like only a basic sponge) offer low quality filtration. Also, filters where you must replace the entire cartridge often, instead of just rinsing the sponge, cost more over time.
User Experience and Use Cases
How you use the filter affects your choice. Think about how often you want to clean it and what kind of fish you keep.
For a beginner with a standard community tank (like tetras or guppies), a simple Hang-On-Back (HOB) filter is often the easiest choice. They are simple to install and maintain. If you have messy fish, like goldfish or cichlids, you need a stronger filter, perhaps an internal or even a small canister filter, because they produce more waste.
User experience is often about maintenance. Can you easily open the filter housing without spilling tank water everywhere? Does it take five minutes or thirty minutes to change the filter floss? Look for reviews that mention easy setup and simple monthly cleaning routines.
10 Frequently Asked Questions (FAQ) About 20-Gallon Tank Filters
Q: What type of filter is best for a 20-gallon tank?
A: The Hang-On-Back (HOB) filter is generally the most popular and easiest choice for 20-gallon tanks. Internal filters also work well.
Q: How often should I clean my 20-gallon filter?
A: You should rinse the mechanical sponge or cartridge every one to two weeks. Never replace all the media at once, as this removes your beneficial bacteria.
Q: Will a filter rated for a 30-gallon tank work on my 20-gallon?
A: Yes, using an oversized filter is often better! It handles waste easily and you can turn the flow rate down if needed.
Q: Do I need to replace the activated carbon every time?
A: You should replace the activated carbon about once a month. Carbon stops absorbing impurities after about 30 days.
Q: Can I run my filter 24/7?
A: Absolutely. Filters must run continuously. Turning them off stops biological filtration, which can quickly harm your fish.
Q: What does “biological filtration” actually do?
A: Biological filtration is where good bacteria live. These bacteria convert toxic ammonia and nitrite (from fish waste) into safer nitrate.
Q: My filter is making a loud rattling noise. What is wrong?
A: A rattling noise usually means the water level is too low, or the intake tube is sucking air. Check the water level and prime the filter if necessary.
Q: Can I add extra filter media to my existing filter?
A: Often, yes, especially with HOB filters. You can usually tuck extra bio-media, like a small bag of ceramic rings, into the filter box for better cleaning.
Q: Which is more important: flow rate or media volume?
A: Both are important, but for a healthy tank, sufficient media volume (especially biological media) is slightly more critical than extreme flow rate.
Q: Are submersible internal filters powerful enough?
A: Yes, many internal filters provide excellent filtration for 20-gallon tanks, especially if you prefer keeping the equipment completely inside the tank.