Do Angelfish Need A Filter? (And Which One To Get)

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A fellow fish enthusiast once told me that he doesn’t include a filter in his 40-gallon tank, which also holds one Angelfish.

But is he doing the right thing? Is a filter mandatory for Angelfish? Can they live without it? How do you pick the right one for them, and which mistakes should you avoid with those delicate creatures?

In this article, I’ll discuss all these questions and more so you leave with all the information you need. Let’s get started.

Should Angelfish Have a Filter?

Yes, angelfish should have a filter in their aquarium. A filter aids in maintaining a clean and healthy environment for the fish.

  • Sensitive Species: Angelfish are susceptible to poor water quality. Filters ensure that harmful toxins and waste, which can stress or harm angelfish, are efficiently removed.
  • Tall Body Shape: Angelfish have a tall and broad body shape which means they produce more waste than smaller fish. A filter effectively handles this increased waste production.
  • Cichlid Family: Being a part of the cichlid family, angelfish can sometimes be territorial or aggressive. A filter helps in dissipating territories by creating water movement, reducing aggressive behaviors.
  • Delicate Fins: Angelfish have long, delicate fins which can easily get infections in stagnant or dirty water. Filters help in maintaining a cleaner environment, minimizing the risk of fin-related ailments.

Also Read: Angelfish Tank Setup

Why It’s Good to Have a Filter for Your Angelfish Aquarium

If you’re still uncertain, let’s delve further to understand why having a filter in an Angelfish tank is crucial:

1. Enhances Water Circulation

A well-circulated aquarium ensures that all areas receive proper oxygenation and helps in evenly distributing heat.

For angelfish, this is particularly important due to their size and activity.

  • Uniform Temperature: With proper circulation, the water’s temperature remains consistent, which is crucial for angelfish who thrive at temperatures between 76°F to 82°F.
  • Aids in Oxygen Distribution: Enhanced water circulation ensures oxygen is uniformly distributed, allowing angelfish to breathe comfortably throughout the tank.
  • Prevents Stagnation: Stagnant areas can harbor harmful bacteria or debris; a good water flow prevents these pockets, reducing risks for angelfish.

2. Minimizes the Frequency of Water Changes

A high-quality filter reduces the number of water changes required, saving time and minimizing the stress on your angelfish.

  • Consistent Environment: Reducing water change frequency ensures that the angelfish experience fewer disruptions in their environment, fostering better growth and health.
  • Less Stress: Constant water changes can stress fish; a filter means fewer water changes, thus less stress for your angelfish.
  • Saves Time: For aquarium hobbyists, less frequent water changes equate to less maintenance time, allowing more time for enjoyment.

3. Offers a Home for Helpful Bacteria

Filters provide a surface for beneficial bacteria to colonize, which are vital in maintaining the aquarium’s nitrogen cycle, making the environment safer for angelfish.

  • Nitrogen Cycle: Filters offer a substrate for bacteria, which convert toxic ammonia to nitrites and then to less harmful nitrates, maintaining a balanced ecosystem.
  • Protection from Toxins: These bacteria play a crucial role in neutralizing harmful substances that can severely affect angelfish health and lifespan.
  • Stable Ecosystem: With a thriving bacterial colony, an aquarium can handle the bioload, ensuring the environment remains stable and healthy for the angelfish.

4. Boosts Water Clarity and Purity

A filter actively removes particulate matter, uneaten food, and organic waste, ensuring the water remains clear and pure, which is essential for the well-being of angelfish.

  • Visual Appeal: Clear water not only offers a better view of your angelfish but also allows them to display their vibrant colors and intricate patterns more vividly.
  • Prevention of Algal Blooms: By removing excess nutrients, a filter can prevent unwanted algal blooms, which could otherwise outcompete angelfish for oxygen.
  • Removal of Contaminants: Filters trap and remove various contaminants, ensuring the water remains pristine, reducing the risk of diseases and promoting healthier angelfish growth.

Filter Options for Angelfish Tanks

When it comes to Angelfish, you have five primary filter types to select from:

1. Sponge Filters

Sponge filters are simple, yet effective devices that utilize a sponge to provide mechanical and biological filtration.

They’re often chosen for smaller tanks or as supplementary filters due to their gentle flow.

  • Gentle Flow: The air-driven mechanism of sponge filters produces a gentle water flow, ideal for angelfish with delicate fins.
  • Biological Filtration: The porous nature of the sponge offers an excellent home for beneficial bacteria, aiding in breaking down waste and harmful toxins.
  • Budget-friendly: Sponge filters are typically inexpensive, making them a cost-effective choice for hobbyists on a budget or for those just starting with angelfish care.

2. Hang-on-Back (HOB) Filters

HOB filters are versatile units that hang on the back of the aquarium, drawing water in, filtering it, and then returning the clean water back to the tank.

  • Ease of Maintenance: HOB filters are easily accessible, making cleaning and cartridge replacements straightforward and hassle-free.
  • Multi-stage Filtration: Many HOB filters offer multi-stage filtration (mechanical, biological, and sometimes chemical), ensuring comprehensive water purification for angelfish.
  • Space-saving: As they hang on the tank’s exterior, HOB filters save space inside the aquarium, allowing for more swimming room for angelfish.

3. Canister Filters

Canister filters are powerful external units suitable for larger angelfish tanks. They are known for their efficiency and multi-stage filtration capabilities.

  • High Volume Filtration: Canister filters handle larger water volumes, making them perfect for spacious angelfish tanks or tanks with multiple inhabitants.
  • Customizable Media: The compartments in canister filters allow hobbyists to customize the filter media, optimizing filtration specific to their angelfish’s needs.
  • Quiet Operation: Operating silently, canister filters won’t disturb the peaceful ambiance of the room, allowing you and your angelfish to coexist in tranquility.

4. Undergravel Filters

Undergravel filters sit beneath the substrate of the aquarium and utilize a lift tube mechanism to pull water through the gravel, serving as both a mechanical and biological filter.

They have been a popular choice for many years.

  • Substrate Filtration: The gravel acts as the filter media, trapping debris and allowing beneficial bacteria to thrive, providing a natural form of biological filtration for angelfish.
  • Aesthetically Pleasing: Since they are hidden beneath the substrate, undergravel filters do not interrupt the visual appeal of the tank, allowing the angelfish and decorations to be the focus.
  • Passive Operation: Operating without any moving parts, undergravel filters tend to have a longer lifespan and operate silently, offering a calm environment for angelfish.

5. Internal Power Filters

Internal power filters are submerged devices placed inside the aquarium.

They are compact and offer both mechanical and biological filtration, making them suitable for mid-sized angelfish tanks.

  • Space Efficiency: Their compact design ensures minimal intrusion into the aquarium’s space, providing angelfish with ample room to swim.
  • Easy Installation: Typically, these filters come with suction cups or other mechanisms for straightforward installation, making setup a breeze for hobbyists.
  • Adjustable Flow: Many internal power filters have adjustable flow rates, allowing aquarists to set the optimal water movement for their angelfish’s comfort and needs.

Key Factors When Picking a Filter for Angelfish

Selecting the appropriate filter for an angelfish tank hinges on understanding both the specific needs of the fish and the characteristics of the tank.

The filter’s primary role is to maintain water clarity and ensure a healthy environment for the angelfish.

  • Tank Size: Filters should process the tank’s volume 4-6 times hourly. For a 50-gallon tank, aim for 200-300 gallons per hour capability.
  • Gentle Flow: Angelfish have delicate fins and prefer calm waters. Choose filters that offer a gentle flow, preventing undue stress.
  • Filtration Efficiency: Clean water is paramount for angelfish. Opt for multi-stage filtration to effectively remove toxins, waste, and other impurities.
  • Maintenance Ease: Regular upkeep is key for filter longevity. Filters that are easy to clean and maintain are preferable for a hassle-free experience.

After taking all these factors into account, I personally opted for the Fluval C4 Power Filter (link to Amazon), and I couldn’t be happier with my choice. Here’s a review:

Can Angelfish Live in a Tank Without a Filter?

Yes, angelfish can survive in a tank without a filter, but their well-being and lifespan might be compromised. Not having a filter places them in a less-than-ideal environment.

  • Stress Levels: In unfiltered water, angelfish may experience heightened stress. Prolonged stress can lead to a weakened immune system, making them more susceptible to diseases.
  • Reduced Activity: The buildup of impurities may cause angelfish to become lethargic. A consistently clean environment typically results in more active and vibrant fish.
  • Life Span Impact: Angelfish can live up to 10 years under optimal conditions. Without proper filtration, their lifespan can be significantly shortened due to the adverse factors they’d endure.

What to Do When Lacking a Filter Setup

If you don’t have a filter in your Angelfish tank, here are some temporary measures you can implement:

1. Don’t Overstock Your Tank

Without a filter, limiting the number of fish is paramount to manage waste and oxygen levels. A less populated tank lessens the burden on water quality.

  • Waste Management: For instance, in a 50-gallon tank, consider keeping 4-6 angelfish instead of 10-12 to control ammonia levels.
  • Oxygen Availability: Fewer fish means fewer gills extracting oxygen. For optimal health, maintaining 5-6 mg/L of dissolved oxygen is crucial.
  • Stress Reduction: An overcrowded environment can lead to territorial disputes. By reducing numbers, you foster a more peaceful habitat.

2. Conduct More Regular Water Changes

In the absence of a filter, manual water replacement becomes a lifeline for angelfish to maintain a healthy environment.

  • Routine Maintenance: Instead of the usual bi-weekly change, consider changing 20-30% of the water every 3 days to remove impurities.
  • Toxin Management: Regular water changes help dilute ammonia and nitrites. Using a test kit weekly can guide the frequency and volume of changes.
  • Temperature Consistency: When changing water, ensure the new water matches the tank’s temperature to avoid shocking the angelfish.

3. Apply Ammonia Neutralizing Agents

Ammonia spikes can be lethal for angelfish. Utilizing neutralizing agents can be a temporary solution when filters are absent.

  • Immediate Action: At the first sign of ammonia (usually detected with test kits), add neutralizers like Fluval Ammonia Remover (link to Amazon) following the product’s instructions.
  • Short-Term Solution: Remember, neutralizers are a temporary fix. It’s crucial to address the root cause, possibly by reducing fish numbers or increasing water changes.
  • Monitor Closely: Regularly test the water. If ammonia levels remain high post-treatment, consider seeking expert advice or acquiring a filter.

4. Incorporate Additional Water Plants

Live aquatic plants serve as natural filters, absorbing nitrates, and providing oxygen. They not only enhance the tank’s aesthetics but actively contribute to a healthier environment.

  • Natural Filtration: Plants like Anubias and Java Fern absorb waste byproducts, helping to keep toxin levels in check.
  • Oxygen Production: During photosynthesis, aquatic plants release oxygen. For instance, a well-lit tank with Elodea can significantly enhance O2 levels during daylight hours.
  • Shelter and Comfort: Beyond their functional benefits, plants offer angelfish hiding spots, reducing stress and mimicking their natural habitat.

Also Read: Do Angelfish Like Light?

5. Utilize Air Stones to Boost Oxygenation

Air stones enhance oxygen levels by dispersing tiny bubbles throughout the tank, promoting better gas exchange at the water’s surface.

  • Increased Surface Movement: This ensures efficient CO2-O2 exchange. For a 50-gallon tank, a medium-sized air stone can improve oxygen distribution effectively. My recommendation: Hygger Aquarium Air Stone (link to Amazon).
  • Stress Reduction: Consistent oxygen levels can reduce fish stress. Observing angelfish for less gasping at the surface post-installation is a positive sign.
  • Enhanced Water Movement: Air stones also aid in circulating water in tank corners, preventing debris accumulation and providing a more uniform environment.

Also Read: Do Angelfish Need A Bubbler?


For those of you who are just skimming through, here’s a short summary:

  • Angelfish require a filter in their aquarium to maintain a clean and healthy environment, especially due to their sensitivity to poor water quality.
  • Filters enhance water circulation, minimize water change frequency, remove harmful compounds, offer a habitat for beneficial bacteria, and boost water clarity and purity.
  • There are five primary filter types suitable for Angelfish tanks: Sponge Filters, Hang-on-Back Filters, Canister Filters, Undergravel Filters, and Internal Power Filters.
  • While angelfish can survive without a filter, it can compromise their well-being and lifespan due to increased stress and reduced water quality.
  • If lacking a filter, temporary measures include not overstocking the tank, conducting regular water changes, using ammonia neutralizers, incorporating live aquatic plants, and using air stones to boost oxygenation.