5 Mistakes Beginners Make With Aquaponics (And How to Avoid Them)
5 Common Aquaponics Mistakes (and How to Avoid Them)
Starting an aquaponics system is exciting, but many beginners run into problems that can lead to frustration and failure.
Whether it’s overstocking fish, neglecting system cycling, or failing to provide enough oxygen, these mistakes can be costly.
The good news?
They’re all avoidable! Here’s a breakdown of five common beginner mistakes and how to prevent them.
1. Overstocking Fish in Your Aquaponics System
The Mistake:
Many new aquaponics enthusiasts assume that more fish means more nutrients for plants, leading to faster growth. However, overstocking your fish tank can cause serious water quality issues, stress your fish, and lead to system crashes.
How to Avoid It:
Start with a low fish-to-water ratio, such as 1 kg of fish per 50 litres of water.
Choose hardy, beginner-friendly fish like goldfish or tilapia that can tolerate minor water fluctuations.
Monitor ammonia and nitrate levels to ensure the system remains balanced.
Avoid rapid increases in fish numbers—gradually build your system's capacity.
Check out my video on how many fish you can have in aquaponics system:
2. Skipping Solids Filtration in Your Aquaponics Design
The Mistake:
Skipping essential filtration components is a common error, especially in DIY systems. Without a solids filter, uneaten food and fish waste can accumulate, leading to clogs, low oxygen levels, and harmful ammonia spikes.
How to Avoid It:
Install a mechanical solids filter (such as a swirl filter or radial flow separator) to remove solid waste before it enters the grow beds.
Use biofiltration media (like expanded clay or bio-balls) to support beneficial bacteria that break down ammonia.
Regularly clean and maintain filters to prevent build-up.
Design your system with proper water flow and drainage to prevent stagnant zones.
Not sure how solids filtration works? This guide explains solids removal in aquaponics.
Check out my video about these 5 common aquaponics mistakes and how to avoid them:
3. Skipping the Cycling Process in Aquaponics
The Mistake:
New aquaponics growers often rush to add fish before establishing the nitrogen cycle, resulting in ammonia toxicity that can kill fish and stunt plant growth.
How to Avoid It:
Cycle your system before adding fish—this means establishing beneficial bacteria that convert ammonia into nitrates.
Use fishless cycling with an ammonia source (such as liquid ammonia or fish food) to allow bacteria to grow before introducing live fish.
Test water parameters regularly, ensuring ammonia and nitrite levels drop to near zero before adding fish.
Be patient—cycling can take 4–6 weeks, but it’s essential for long-term success.
Watch my video on how to cycle your aquaponics system:
4. Overfeeding Fish and Causing Water Imbalance
The Mistake:
It’s tempting to feed fish more than they need, but uneaten food decays in the water, leading to poor water quality, oxygen depletion, and excess waste build-up.
How to Avoid It:
Feed fish small amounts (only what they can eat in 2–3 minutes).
Remove uneaten food to prevent water contamination.
Adjust feeding based on water temperature—fish eat less in colder conditions.
Avoid relying on automatic feeders without monitoring—overfeeding can happen quickly.
Learn more about choosing the right fish in aquaponics here.
Want to get your Eyes and Hands on the FREE Online Aquaponics Essentials Course?
This is a great free resource to really understand how aquaponics is a sustainable ecosystem that will grow your organic food is a productive way.
You learn how all the 'parts' make up the 'whole', and helps to give you the foundations of understanding aquaponics.
Sign up HERE
5. Low Oxygen Levels in Aquaponics Systems
The Mistake:
Many beginners underestimate the importance of oxygen in aquaponics. Low oxygen levels stress fish, slow plant growth, and hinder beneficial bacteria activity.
How to Avoid It:
Use air stones or aerators to maintain high oxygen levels.
Ensure good water circulation with a reliable pump.
Avoid overcrowding fish, as they consume oxygen quickly.
Check dissolved oxygen levels regularly, especially in warm weather when oxygen decreases.
Place aeration devices strategically—oxygen should reach fish, plant roots, and bacteria colonies.
Check out my video about whether your aquaponics system need an air pump to add oxygen:
Build a Thriving Aquaponics Garden
By avoiding these common mistakes—overstocking fish, poor system design, skipping cycling, overfeeding, and neglecting oxygen—you’ll create a balanced, thriving aquaponics system.
Take the time to plan your setup, monitor water parameters, and make gradual adjustments as needed.
With the right approach, aquaponics can be a rewarding, low-maintenance way to grow fresh food at home!
Explore the full Aquaponics Essentials Course to fast-track your setup.
Learn More About Aquaponics
Check out the COURSES page to learn how you can get started with aquaponics now. Click HERE.
Want to get your Eyes and Hands on the FREE Online Aquaponics Essentials Course?
This is a great free resource to really understand how aquaponics is a sustainable ecosystem that will grow your organic food is a productive way.
You learn how all the 'parts' make up the 'whole', and helps to give you the foundations of understanding aquaponics.
Sign up HERE
Check out my YouTube Channel 'Candy The Aquaponics Lady'
Aquaponics is an ecosystem, and with anything it takes time to learn how it works. So, sit back and binge watch my 'how to' playlist and the 'Water Quality Made Simple' Playlist, and learn the next steps in your aquaponics system as you create the ecosystem.
Here are the next 2 videos I recommend you watching to create your ecosystem ~ before you add any fish
How Aquaponics Works as an Ecosystem
Why aquaponics is the best form of gardening for you
Want to help out (donate some fish food) and Feed my Fish?? (They don't drink coffee)
Candy Alexander is a dedicated aquaponics enthusiast with a wealth of formal training in aquaculture. Over the past 15 years, Candy has been deeply immersed in both commercial and backyard aquaponics, honing her skills and expertise in this sustainable farming method.
Candy's passion lies in making aquaponics accessible to everyone. With a mission to simplify aquaponics, she believes that anyone can embark on this sustainable journey.
She encourages those new to aquaponics to "kick the tires" without a significant financial investment. Her guidance focuses on helping people start their aquaponics journey with small-scale systems, ensuring a low barrier to entry for newcomers.
Candy shares practical tips, step-by-step guides, and personal stories to inspire and guide readers on their aquaponics adventure. Whether you're a seasoned farmer or a curious beginner, Candy Alexander is your go-to source for simplifying aquaponics and fostering a sustainable gardening experience.
