Where to Put Ceramic Rings in a Fish Tank

If you’re setting up an aquarium and wondering where to put ceramic rings in a fish tank, you’re already on the right path to becoming a smart fish keeper. Ceramic rings are one of the most essential filtration media in modern aquariums. They help maintain crystal-clear water, support healthy fish, and make your tank’s ecosystem thrive.

But — and this is key — where you place them matters just as much as having them. Put ceramic rings in the wrong section of your filter, and they won’t work effectively. Place them correctly, and you’ll have the perfect biological filtration setup that can keep ammonia and nitrite levels near zero.

This in-depth guide breaks down everything you need to know about ceramic rings — what they do, how they work, and exactly where and how to place them for maximum performance.

Understanding What Ceramic Rings Are

Before you decide where to put ceramic rings in your fish tank, you should understand what they are and how they function.

Ceramic rings are porous filtration media made from baked clay or ceramic material. Each ring is filled with tiny pores and tunnels that provide an enormous surface area for beneficial bacteria to grow. These bacteria form the backbone of your tank’s biological filtration system, converting harmful waste into safer compounds.

In short:

• They don’t filter debris (that’s mechanical media’s job).
• They don’t add chemicals (that’s chemical media’s job).
• They host bacteria that keep your tank water healthy.

The shape — a hollow ring — isn’t random. It allows maximum water flow through and around the media, ensuring oxygen-rich water reaches the bacteria colonies inside.

Why Ceramic Rings Are Crucial in Aquarium Filtration

Every fish tank has a nitrogen cycle — a natural process that breaks down fish waste, uneaten food, and decaying plants.

Here’s how it works:

1. Ammonia (NH₃) from fish waste is produced constantly. It’s toxic, even at low levels.
2. Nitrosomonas bacteria grow on surfaces and convert ammonia into nitrite (NO₂⁻).
3. Nitrobacter bacteria then convert nitrite into nitrate (NO₃⁻), which is far less toxic.

Ceramic rings are where these beneficial bacteria live. Without them, your tank could experience ammonia spikes that can stress or even kill your fish.

They’re basically the home base of your tank’s good bacteria.

How Ceramic Rings Work Inside the Filter

When water flows through your aquarium filter, it passes through different media stages:

1. Mechanical Filtration (sponges, filter floss, pads) – removes visible debris and particles.
2. Biological Filtration (ceramic rings, bio balls, lava rock) – supports bacterial colonies to neutralize toxins.
3. Chemical Filtration (activated carbon, resins) – removes odors, discoloration, and dissolved impurities.

Ceramic rings belong squarely in the biological stage — right after the water has been mechanically cleaned.

That means you should always put ceramic rings after your sponge or filter floss, so only clean water (free of big particles) reaches them. This prevents the pores from clogging and ensures long-term effectiveness.

Where Exactly to Put Ceramic Rings in a Fish Tank

Now for the core question: where to put ceramic rings in a fish tank.

It depends on your filtration system type, because each has a different flow pattern. Let’s break it down.

1. In a Canister Filter (External Filter)

Canister filters are powerful and common in larger aquariums. They typically have several trays or baskets for different media layers.

Here’s the correct order for media placement (bottom to top):

1. Bottom Tray (Mechanical Filtration): coarse sponge or filter pad to catch large debris.
2. Middle Tray (Biological Filtration): ceramic rings, bio balls, or similar media.
3. Top Tray (Chemical Filtration): activated carbon or Purigen (if used).

Since water usually flows from the bottom upward, ceramic rings should sit in the middle basket — after mechanical filtration but before chemical media.

This ensures clean, oxygenated water reaches the bacteria without clogging the pores with waste.

Pro Tip: Fill an entire tray with ceramic rings if you have a large fish load. The more surface area, the more bacteria your tank can support.

2. In a Hang-On-Back (HOB) Filter

Hang-on-back filters are common for medium-sized aquariums. They’re compact and easy to maintain, but have less room for media customization.

Best placement:

• Put ceramic rings below or behind the filter cartridge, where water flows after passing through the filter pad.
• Some aquarists remove the manufacturer’s carbon cartridge and replace it with a mesh bag of ceramic rings — improving biological filtration dramatically.

In most HOB filters, water flows from front to back or top to bottom, depending on the model. Always make sure the ceramic rings come after the sponge or pad.

Pro Tip: If space is tight, use smaller-sized ceramic rings or crush them slightly to fit them into a mesh bag.

3. In an Internal Filter (Submersible Filter)

Internal filters sit directly inside the tank and are typically used in small aquariums.

In these systems:

• Place ceramic rings in the compartment after the sponge but before any chemical media.
• If there’s no separate compartment, put ceramic rings in a small mesh or nylon bag and position it near the filter outlet where water flow is strongest.

This helps ensure constant oxygen supply to the bacteria colonies.

4. In a Sponge Filter

Sponge filters are popular in breeding and shrimp tanks because they provide gentle filtration and aeration. However, they have limited biological media space.

Here’s how you can still use ceramic rings:

• Place ceramic rings around the base of the sponge filter, where water movement is strong.
• Alternatively, put them in a separate mesh bag near the air stone or bubble outlet to maximize flow-through.

It’s a simple hack that increases your tank’s biological capacity without changing your filter setup.

5. In a Sump Filter (for large tanks or marine setups)

A sump filter gives you complete control over media placement — perfect for serious aquarists.

Ideal layout (based on water flow direction):

1. First chamber: mechanical filtration (filter socks, sponges).
2. Second chamber: ceramic rings and other bio media.
3. Third chamber: chemical filtration (carbon, resins) or return pump section.

Ceramic rings go in the second chamber, completely submerged, so bacteria can thrive with a steady water flow.

Pro Tip: If your sump has extra space, mix ceramic rings with other porous media like lava rock or bio-home to create a powerful bacteria zone.

6. In a Filterless or Low-Tech Setup

Even if you don’t use a traditional filter, you can still add ceramic rings to promote biological stability.

Place them in:

• A mesh bag hidden behind decorations or plants.
• A corner of the tank with gentle water flow from an air stone or circulation pump.

They’ll still host beneficial bacteria and help stabilize your nitrogen cycle — though not as efficiently as in a full filtration system.

How Many Ceramic Rings Do You Need?

There’s no universal rule, but a general guideline is 1 pound (450g) of ceramic rings per 20 gallons of water for standard freshwater tanks.

However, the amount also depends on:

• Fish population (more fish = more waste).
• Tank size and flow rate.
• Type of filter (canister filters can hold more media).

When in doubt, more is better — but don’t overcrowd your filter. You want water to flow freely through the media for optimal bacterial performance.

The Correct Way to Prepare Ceramic Rings

When you first buy ceramic rings, don’t just dump them into your filter. Follow these steps:

1. Rinse Thoroughly
   New ceramic rings are dusty from manufacturing. Rinse them under tap water until the water runs clear.
2. Soak in Dechlorinated Water
   If you’re cycling a new tank, soak the rings in dechlorinated water for a few hours to remove any residual dust or chemicals.
3. Place Them in a Mesh Bag
   This makes them easier to clean or replace later. Most aquarium stores sell fine mesh media bags for this purpose.
4. Avoid Boiling or Baking
   Heat can crack or damage the porous structure. Always rinse with water only.

Maintenance Tips — Keeping Ceramic Rings Effective

Ceramic rings can last for years, but they need minimal maintenance to keep performing well.

• Never replace all rings at once.
  They host essential bacteria. Replacing all of them will crash your tank’s nitrogen cycle.
• Rinse them gently in old tank water (not tap water) during filter cleaning. Tap water’s chlorine can kill beneficial bacteria.
• Replace small portions (25–30%) every 12–18 months if they become clogged or break apart.
• Avoid over-cleaning. Some slimy buildup is beneficial — that’s the biofilm where bacteria live.

Ceramic Rings vs. Other Biological Media

While ceramic rings are popular, they aren’t your only option for biological filtration. Here’s how they compare:

Ceramic rings strike the perfect balance of performance, price, and ease of use, which is why they’re a favorite among both beginners and experts.

Common Mistakes to Avoid

Even experienced aquarists sometimes misuse ceramic rings. Here are the top mistakes:

1. Placing Them Before Mechanical Media
   If dirty water hits ceramic rings first, debris clogs the pores and suffocates bacteria. Always place them after sponges or filter pads.
2. Cleaning with Tap Water
   Chlorinated water kills beneficial bacteria. Always rinse in old tank water.
3. Replacing All Rings at Once
   This destroys your biological colony. Replace in sections over time.
4. Lack of Water Flow
   If water barely moves around the rings, bacteria won’t get enough oxygen. Position them where flow is steady and consistent.
5. Ignoring Maintenance
   Even though ceramic rings last years, clogged media can reduce efficiency. Clean lightly every few months.

Bonus Tip — Layering Media Like a Pro

To get the best from your filter, arrange your media in proper sequence:

1. Mechanical Media: Sponge, filter floss, or pad.
2. Biological Media: Ceramic rings, bio balls, or lava rock.
3. Chemical Media: Activated carbon or other specialized resins.

This setup ensures clean, oxygen-rich water flows over your bacteria, letting them perform at maximum capacity.

Why Placement Matters So Much

The placement of ceramic rings in your fish tank filter determines how efficiently the nitrogen cycle functions.
When water hits the rings at the right stage, the bacteria thrive and stabilize your water chemistry. When placed incorrectly, they can clog, suffocate, and stop working.

In essence, proper placement equals healthy water and thriving fish.

Frequently Asked Questions (FAQs) About Ceramic Rings in Fish Tanks

1. Where should ceramic rings go in a fish tank?

Ceramic rings should be placed in the biological filtration stage of your filter — after mechanical filtration (like sponge or filter floss) but before chemical media (like activated carbon). Proper placement ensures water is clean when it passes through the rings, allowing beneficial bacteria to thrive.

2. Can ceramic rings be placed directly in the tank without a filter?

Yes, but it’s less effective. In filterless setups, ceramic rings should be placed in a mesh bag near areas with good water flow, such as behind decorations, near an air stone, or next to a circulation pump. This maximizes oxygen exposure for bacteria.

3. How many ceramic rings do I need for my tank?

A general rule of thumb is 1 pound of ceramic rings per 20 gallons of water. Adjust based on:

• Fish population (more fish = more waste)
• Tank size
• Flow rate of your filter

More ceramic rings increase surface area and support more beneficial bacteria.

4. Can ceramic rings last forever?

Ceramic rings can last years, often 5–10+ years, if maintained properly. They don’t degrade like sponges, but they can become clogged with debris over time. Partial replacement or gentle rinsing is recommended every 12–18 months.

5. How do I clean ceramic rings without killing the bacteria?

Rinse ceramic rings gently in old tank water, not tap water. Tap water contains chlorine, which can kill beneficial bacteria. Only replace a portion of the rings at a time to maintain the biological colony.

6. Can I mix ceramic rings with other media?

Absolutely. You can combine ceramic rings with:

• Bio balls
• Lava rock
• Sintered glass media

Mixing can increase surface area and improve biological filtration. Just ensure the rings remain after mechanical filtration for optimal performance.

7. What happens if I place ceramic rings before mechanical filtration?

If ceramic rings receive dirty water first, debris can clog their pores, reducing water flow and killing bacteria. Always position ceramic rings after sponges or filter pads in your filtration system.

8. Can ceramic rings remove ammonia and nitrites by themselves?

Ceramic rings don’t directly remove ammonia or nitrites — they host beneficial bacteria that process these compounds naturally through the nitrogen cycle. Proper placement and flow are essential for this biological filtration to work effectively.

9. Do ceramic rings work in saltwater tanks?

Yes. Ceramic rings function in both freshwater and marine aquariums. Just ensure they are placed in areas with good water flow and are rinsed in dechlorinated or saltwater when needed.

10. Can I overfill my filter with ceramic rings?

Overfilling can restrict water flow, which reduces oxygen supply to the bacteria and decreases filtration efficiency. Fill the compartment loosely or in layers to allow water to circulate freely.

Conclusion: Maximizing Your Aquarium’s Health with Ceramic Rings

Knowing where to put ceramic rings in a fish tank is one of the simplest yet most effective ways to ensure your aquarium stays clean, safe, and thriving. These rings are the cornerstone of biological filtration, hosting colonies of bacteria that convert harmful ammonia and nitrites into less toxic nitrates.

Correct placement — after mechanical filtration and with good water flow — ensures these beneficial bacteria flourish. Using ceramic rings correctly reduces stress on fish, stabilizes water chemistry, and helps maintain a beautiful, clear tank.

Whether you use a canister filter, HOB filter, internal filter, or even a low-tech setup, ceramic rings are adaptable and highly efficient. They last for years, are easy to maintain, and dramatically improve the health and longevity of your aquatic ecosystem.

In essence, ceramic rings are more than just decoration or filler — they are the engine that keeps your fish tank biologically balanced. Place them right, care for them properly, and you’ll have a thriving, low-maintenance aquarium for years to come.