What’s the Best Aquarium Filter? A Beginner-Friendly Guide to Filtration Types
Choosing a filter is one of the most important decisions when setting up your aquarium. With so many options out there and with all these terms such as mechanical, biological, chemical, sponge, hang-on-back, canister it can feel like a lot to take in.
But don’t stress. In this guide, we’ll break it all down in a way that’s easy to understand, even if you’re just getting started. You’ll learn the difference between the three main types of filtration, the pros and cons of the most common filter designs, and how to choose the right one for your setup.
What Are the Three Types of Filtration?
Most filters do more than one job at once, but it’s helpful to know what those jobs actually are.
Mechanical Filtration – Catching the Gunk
Mechanical filtration physically removes particles like uneaten food, fish poop, plant debris, and other waste from your water. Think of it as your tank’s vacuum cleaner.
Media examples: Sponges, filter pads, floss, Filter wool.
- Tip: Rinse mechanical media in old tank water (not tap) during water changes to avoid killing benificial bacteria.
- Note: Needs regular cleaning to prevent clogs and ammonia spikes.
Biological Filtration – The Real MVP
Biological filtration is what keeps your tank water safe over time. It gives beneficial bacteria a place to grow, this bacteria that break down toxic ammonia and nitrite into less harmful nitrate through the nitrogen cycle, this bacteria is know as benificial bacteria.
Media examples: Ceramic rings, sponge, bio balls, lava rock.
- Tip: Never fully clean or replace all your biological media at once—this can crash your cycle!
Chemical Filtration – The Finishing Touch
This is the optional one. Chemical filtration targets specific impurities like tannins, odours, medications, or excess nutrients.
Media examples: Activated carbon, phosphate removers, zeolite.
- Tip: Replace chemical media regularly for it to stay effective. It’s not usually essential for most tanks, but can be useful in certain situations (like after medication or when trying to clear up yellow water).
- You can find all types of filtration media that will benefit your aquarium in our All Media Collection!
Filter Types Pros and Cons
Now that you understand what filters do, let’s look at the most common filter types and when you might want to use them.
Sponge Filters:
Super popular in breeding tanks, shrimp tanks, and with hobbyists who want something gentle and easy.
✅ Cheap and beginner-friendly.
✅ Great biological filtration.
✅ Safe for baby fish and shrimp.
✅ Easy to clean.
❌ Needs an air pump, check valve and air tubing.
❌ Not the best for high-flow or high-stock tanks.
- Best for: Small tanks, breeding tanks, shrimp setups and hospital tanks. You can find more information in our Sponge Filter Collection!
Internal Filters (Submersible):
These go inside your tank, usually suction cupped to your aquarium glass, these filters pump water through filter media using a small built-in motor.
✅ Easy to install and affordable.
✅ Combo of mechanical + biological filtration.
✅ Great for smaller tanks.
❌ Takes up space inside your tank and can sometimes be bulky.
❌ May not provide enough flow for bigger setups.
- Best for: Small community tanks, budget builds, quarantine setup. Ceck them out in our Submersible Filters Collection!
Hang-On-Back (HOB) Filters
A classic go-to for many beginners and even advanced hobbyists. It hangs on the back of your tank and draws water up through media and back out into your aquarium like a mini waterfall.
✅ Easy to access and maintain.
✅ Handles all three types of filtration.
✅ Good for medium-sized tanks.
✅ Low surface agitation, good for keeping floating plants and fish that prefer low flow.
❌ Can be noisy over time.
❌ May not be powerful enough for big tanks.
- Best for: Tanks under 150L, planted tanks, beginner setups
Canister Filters
A powerful external filter that sits under your tank and pushes water through multiple layers of media. Canister Filters are one of my personal favourite choices for bigger community tanks.
✅ Excellent for large or heavily stocked tanks.
✅ Highly customisable with different media.
✅ Can include UV, inline heaters, CO₂ diffusers, etc.
❌ More expensive.
❌ Takes longer to clean.
- Best for: Tanks over 150–200L, goldfish tanks, cichlid tanks, planted tanks with CO₂. You can find out more information on canister filters by searching our Canister Filter Collection!
Undergravel Filters (UGF)
These sit under your gravel and pull water through the substrate. They’ve been around forever, but aren’t super common in modern setups.
✅ Low-tech and long-lasting.
✅ Simple design.
❌ Traps debris under the gravel.
❌ Not great for planted tanks or fine substrates.
- Best for: Old-school setups, tanks with coarse gravel, basic fish-only aquariums.
Which Filter Should You Choose
Here’s a quick reference based on common setups:
Tank Setup Filter Suggestions:
Shrimp or fry tank:
Sponge filters 1-2 depending on tank size and bio load.
20–60L community tank:
Sponge and/or internal filter.
75–150L planted tank:
HOB or small to medium canister filter.
200L+ or heavy bioload:
Medium to large canister filter.
Low-tech gravel tank:
Undergravel filter (optional sponge backup).
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Pro Tip: You can absolutely combine filters too! Many hobbyists run a sponge filter alongside a HOB or canister for extra biological support and backup in case one fails.
Final Thoughts: Dont Overthink It!
The “best” filter is the one that suits your tank, your fish, and your maintenance style. Start with something easy, learn as you go, and upgrade when you’re ready. Every tank is different and there’s no shame in keeping it simple!
If you’re unsure what filter to pick, feel free to reach out for advice, or check out our stores Filter Collection for beginner-friendly options!