How To Cycle An Aquarium Without Fish

If you’re new to the world of aquariums, you might be wondering what all the fuss is about when it comes to cycling. 

You’ve heard about the importance of cycling your aquarium, but you don’t want to introduce fish until you’re absolutely sure it’s safe for them. 

Well, you’re in the right place! In this guide, I’ll delve deep into how to cycle an aquarium without fish and uncover the secrets to creating a thriving aquatic ecosystem. 

But Before we dive into fishless aquarium cycling, let’s understand first what aquarium cycling is all about. 

What Is Aquarium Cycling?

Aquarium cycling is like preparing a safe and comfortable home for fish in a fish tank. It’s important because it helps make the water in the tank safe for the fish to live in. 

You see when you have a new tank, there are chemicals in the water that can harm the fish. But through cycling, we make these harmful chemicals change into something less dangerous, so the fish can live happily.

Now, let’s talk about fishless aquarium cycling, which is a method to achieve this safe environment without using real fish to do it.

What Is The Purpose Of Cycling Aquariums?

Creating a new home for fish in an aquarium comes with a challenge. Even though the water may appear clean, there are hidden issues. Here’s why we do it.

1. Establishing A Safe Environment

  • New aquariums often have high levels of ammonia, which is toxic to fish. Cycling helps build up beneficial bacteria that convert ammonia into less harmful substances, like nitrites and nitrates.
  • These bacteria create a biological filter that makes the water safe for fish. Without this cycle, ammonia and nitrite levels can spike, posing a serious risk to your aquatic pets.

2. Balancing Water Parameters:

  • Cycling also stabilizes key water parameters. Ammonia, nitrite, and nitrate levels are kept in check, preventing harmful fluctuations that can stress or harm fish.
  • pH levels, temperature, and hardness can also become stable during the cycling process, creating a consistent and comfortable environment for your fish.

3. Ensuring Fish Well-Being

  • Cycling an aquarium is a fundamental step in responsible fishkeeping. It demonstrates your commitment to providing a healthy habitat for your aquatic companions.
  • A well-cycled aquarium reduces the chances of fish experiencing stress, illness, or even death due to poor water quality.

4. Preventing Toxin Accumulation:

  • Toxic substances can accumulate in new aquariums, leading to fish suffering from conditions like ammonia poisoning or nitrite toxicity. Cycling prevents these toxins from building up.
  • Nitrate, a byproduct of the cycling process, is less harmful than ammonia and nitrite. Regular water changes can help keep nitrate levels in check.

5. Supporting Longevity

  • When an aquarium is properly cycled, the fish are more likely to live longer, healthier lives. This leads to a more rewarding and enjoyable experience for the aquarium owner.

6. Minimizing Maintenance

  • A well-established cycle can reduce the need for frequent water changes and maintenance, making fishkeeping more manageable and less time-consuming

The purpose of cycling an aquarium is to create a safe, stable, and welcoming environment for your aquatic pets. 

It prevents the buildup of harmful toxins, maintains water quality, and supports the well-being and longevity of your fish. 

Proper cycling is an essential step in responsible fishkeeping and contributes to a thriving and enjoyable aquarium.

What Is The Typical Duration For An Aquarium To Cycle?

Being patient is crucial when you’re cycling in an aquarium. Normally, it takes some time for this process to happen naturally, usually ranging from 2 to 6 weeks. 

During this period, beneficial bacteria grow and establish themselves to make the water safe for your fish. But, here’s the good news: there are ways to speed up this cycle without harming any fish. It’s called “fishless cycling.” 

With this method, you can help the beneficial bacteria grow faster and have your aquarium ready for fish in a shorter time. 

So, by choosing the right approach, you can ensure that your aquarium becomes a safe and happy home for your fish as soon as possible.

What Equipment Is Necessary For Setting Up An Aquarium?

Before we jump into the interesting world of fishless cycling, let’s make sure you have all the necessary equipment.

1. Tank: when it comes to setting up an aquarium, the tank is your starting point. The size of the tank matters because it determines how much effort you’ll need to put in to keep everything in good shape. 

So, it’s a good idea to choose a tank size that matches your level of experience with fishkeeping.

2. Filter: A filter is like a helper for your aquarium. It’s a bit like a janitor that keeps the water in the tank clean and safe for your fish. Just remember to pick a filter that matches the size of your tank so it can do its job effectively.

3. Heater: A heater is like a thermostat for your fish’s home. It’s important because some fish need the water to be just the right temperature to feel comfortable and stay healthy. So, a heater helps keep the water at the perfect temperature for them.

4. Substrate: The substrate is basically the stuff that covers the bottom of the tank, like the ground in a garden. You can use gravel or sand for this. 

It’s not just for looks; it’s actually important because it gives a home to helpful bacteria. These bacteria play a big role in keeping the water clean and healthy for your fish.

5. Test Kits: Test kits are like tools to help you understand your fish’s water. They check important things like ammonia, nitrite, nitrate, and pH. 

These tests help you know if the water is good for your fishy pals or if something needs fixing. Think of it as a way to make sure your fish have the right kind of water to swim in and stay healthy.

6. Water conditioner: A water conditioner is like a guardian for your fish’s water. It makes tap water safe for your fishy friends by getting rid of harmful stuff like chlorine. 

Imagine it as a special potion that turns regular water into a cozy and safe swimming place for your fish. It’s like giving them a comfy and clean home to live in.

7. Decorations: Decorations are the fun stuff you put in the tank to make it appealing for your fish. It’s like creating a cozy and interesting home for them. 

You can add things like plants, rocks, and cool ornaments to make their environment more enjoyable.

8. Using a Biological Starter: A biological starter is like a helper for your aquarium. It’s made of good bacteria that can start the cycling process. These bacteria are like little workers that clean up the water and make it safe for fish. 

It’s a bit like having friendly janitors in your fish tank, making sure everything is tidy and ready for your fish to move in.

Now, let’s move on to the fun part of getting your aquarium ready for fish without actually adding fish yet.

Steps for Cycling an Aquarium

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1. How To Cycle An Aquarium Without Fish?

Cycling an aquarium without fish, which is called “fishless cycling,” is a special and kind way to get your aquarium ready. Here’s how to do it:

  • Add Ammonia: Put something in the tank that gives off ammonia, like fish food or pure ammonia. It’s like putting a pretend fish in there to make the water a little dirty.
  • Monitor Ammonia Levels: Use a test kit to check how much ammonia is in the water. This helps you keep an eye on how dirty the water is getting.
  • Beneficial Bacteria Development: When the water gets dirty, good bacteria start to grow. These friendly bacteria change the yucky ammonia into something called nitrites, which are not as harmful.
  • Nitrite Levels: Keep checking to see how many nitrites are in the water. They will go up and then come down. This is a sign that your tank is getting ready for fish.
  • Nitrate Production: Nitrites will slowly change into nitrates, which are even less harmful. Once the nitrate levels stay steady, your tank is all set for fish to move in.

This process might take some time, but it’s worth it to make sure your fish have a clean and safe home.

2. Cycling With Fish

Cycling your aquarium with fish is like moving into a house that’s not quite ready. It can be tough for your fish pals, so you need to take extra care. 

  • Keep a Close Watch: You have to be like a fish detective and check the water often. Look out for things like ammonia and nitrite levels. If they get too high, it’s like having a messy and unsafe home for your fish.
  • Frequent Water Changes: To keep your fish happy and healthy, you’ll need to change a lot of the water regularly. It’s a bit like giving your fish a fresh, clean room to live in while the construction work continues. This helps them feel more comfortable even during the building process.

Remember, while cycling with fish is possible, it’s not the easiest option for them. So, be extra cautious and make sure your fish buddies stay safe and cozy.

3. Cycling With Plants

When you cycle your aquarium with plants, you bring in some green helpers to improve the environment.

1. Natural Ammonia Absorption: Plants act like natural sponges, soaking up ammonia, which is a bit like the mess in your aquarium. This helps keep the water clean and safe for your fish.

2. Extra Space For Good Bacteria: Plants also create more surfaces for good bacteria to grow. These bacteria act as the cleanup crew, making the water healthier for your fish. With more places to live on the plants, they can work faster.

So, having plants in your aquarium is like having natural partners that speed up the cleaning process, making it a better place for your fishy friends.

4. Using Fish Food To Cycle The Aquarium

When you’re setting up your aquarium without fish, you can use fish food to make the water right for your future fishy pals. 

  • Fish Food As Ammo: Instead of fish, use a bit of fish food. It’s like a tool that makes the water a bit messy, and that’s what you want. Put a small amount of fish food in the water. As it breaks down, it releases ammonia.
  • Let It Decompose: You don’t need to do anything fancy. Just drop the fish food in the tank and leave it there. Over time, it breaks down and makes ammonia, which is the first step in getting your tank ready for fish.

5. Using Pure Ammonia To Cycle The Aquarium

Another way to prepare your aquarium without fish is by using pure ammonia. This method gives you more control over the ammonia levels in your tank, but it needs careful handling. 

  • Precise Ammonia Dosing: Instead of fish or fish food, you add a small amount of pure ammonia to the water. This is like using a dropper to put in just the right amount of ammonia. It helps you control how dirty the water gets.
  • Handle with Care: Pure ammonia is strong stuff, so you have to be careful. Add only a tiny bit at a time, and regularly check the ammonia levels to make sure they don’t get too high. It’s like being a scientist and measuring things precisely.

Using pure ammonia might take a bit more attention, but it’s a way to have a tight grip on the cycling process to make your aquarium safe and comfy for your future fishy residents.

6. Keep Your Aquarium Clean And Clear With ALGONE

ALGONE is a handy product that can improve your aquarium. 

  • Speeds Up Cycling: ALGONE helps your aquarium get ready for fish faster. It’s like giving your aquarium a turbo boost, so it’s fish-ready in less time.
  • Clears Water: ALGONE does a fantastic job of keeping the water super clear, like a sparkling crystal. It has good bacteria that clean up the water, and it removes extra things that can make yucky algae grow.

So, when you use ALGONE, you’re giving your aquarium a hand to stay clean and ready for your fishy friends. It makes the water clear and speeds up the process.

What Are The Disadvantages Of Fishless Cycling?

Fishless cycling is a good way to get your aquarium ready, but it does have some things to keep in mind:

  • Time And Patience: Fishless cycling takes longer than using fish to cycle your aquarium. You’ll have to wait for a few weeks before it’s safe to add fish. This means you won’t get to enjoy your fishy friends in your tank right away.
  • Regular Testing: You’ll need to test the water in your aquarium regularly during the fishless cycling process. This involves checking the levels of ammonia, nitrites, and nitrates to make sure they are at safe levels for fish. This can be a bit of work and might seem like a hassle.
  • Monitoring: Along with testing, you’ll have to keep a close eye on the conditions in your tank. If something goes wrong with the cycling process, you’ll need to make adjustments to fix it. This means you’ll need to be attentive and responsible in maintaining the tank environment.

Fishless cycling is a safe and humane method, but it requires you to be patient, do regular water testing, and keep a watchful eye on your aquarium’s conditions, which can be more work compared to cycling with fish.


In summary, cycling your aquarium without fish is a caring and responsible approach to creating a stunning underwater home. 

While it demands time and effort, the rewards are remarkable – your fish will thrive in a peaceful, beautiful space. Just remember that patience is essential. 

As your tank evolves, you’ll be rewarded with the enchanting beauty of a well-cycled aquarium. If you have any questions or concerns, please don’t hesitate to ask. Thank you for reading.


Do dead fish help cycle a tank?

No, dead fish do not help cycle a tank. In fact, it’s not a good idea to use dead fish for cycling.

The cycle relies on beneficial bacteria to break down ammonia, and these bacteria need live sources of ammonia to establish themselves. Using live fish food or ammonia solutions is a much safer and more humane way to cycle your tank.

Can I add fish after 24 hours?

Adding fish to your tank after only 24 hours is not recommended. Cycling a tank properly usually takes several weeks to ensure a safe and stable environment for fish. Rushing this process can lead to stressful and harmful conditions for the fish.

It’s important to wait until your tank has completed the cycling process, as indicated by stable water parameters, before introducing any fish.

Should you make water changes while cycling?

During the cycling process, it’s generally not advisable to make large water changes. This is because the cycle relies on the buildup of beneficial bacteria, and changing too much water can disrupt their growth.

However, if ammonia or nitrite levels become extremely high and dangerous for the fish, it’s better to do a partial water change to protect their health. It’s essential to monitor water parameters regularly and take action if they become harmful to the fish.

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  3. How To Trim Aquarium Plants
  4. How To Clean An Aquarium Filter
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