Goldfish in Aquaponics: Easy, Low-Maintenance Fish for Beginners
Goldfish are a great place to start in aquaponics
When setting up a home aquaponics system, especially in a small space, choosing the right fish can make or break your experience. For beginner aquaponics enthusiasts, goldfish are one of the easiest, most affordable, and low-maintenance options to start with.
Whether you're using a bathtub, barrel, or compact tank, goldfish can thrive, and help your plants thrive too!
If you're working with a compact space, check out this DIY fish tank aquaponics setup guide to learn how to build a simple system using basic tools and containers.
Why Goldfish Are Ideal for Aquaponics
Many people assume aquaponics needs expensive or edible fish like tilapia or perch, but goldfish offer huge benefits for small-scale and DIY systems:
Hardy and resilient – Goldfish can withstand temperature fluctuations and minor water quality issues, making them more forgiving for new aquaponics growers.
Affordable and easy to find – Unlike silver perch, tilapia or other edible fish, goldfish are widely available at pet stores and require minimal initial investment.
Excellent waste producers – Their steady output of ammonia-rich waste provides essential nutrients for plant growth.
Low maintenance – Goldfish don’t require heaters (in most climates) or complex diets, making them one of the simplest fish to care for.
Not sure if goldfish are the right fit? Explore this guide to choosing the best fish for your aquaponics system to compare your options.
Want to get your Eyes and Hands on the FREE Online Aquaponics Essentials Course?
This easy-to-follow online course helps you understand how each part of the aquaponics system works together to grow fresh, organic food in a compact space.
Sign up HERE and start building your own thriving ecosystem today.
How to Care for Goldfish in a Home Aquaponics System
While goldfish in aquaponics are low-maintenance, a few basics go a long way in keeping them, and your system, healthy.
1. Tank Size and Stocking Rates
Goldfish need at least 40 litres (10 gallons) of water per fish for a healthy environment (depending on the grow out size of the goldfish).
Avoid overcrowding—more space means better water quality and less maintenance.
If using a bathtub or barrel, aim for 5-10 goldfish per 200-liter system, depending on filtration capacity.
Choosing the right container makes a big difference to fish health and system success, check out this guide to selecting the best fish tank for aquaponics.
2. Feeding Schedule
Feed once or twice daily, providing only as much as they can eat in 2-3 minutes.
Choose high-quality pellets for better nutrition and less waste. It is common to buy cheap food for goldfish, however think about the whole food chain here. Healthy fish, with good nutrition, means that the micronutrients will be available in their waste for the plants. Feeding goldfish cheap flakes and expecting them to be healthy, is like us eating 2-minute noodles everyday, and expecting us to get the best nutrition possible.
Avoid overfeeding—uneaten food can cause water quality problems.
3. Water Quality Management
Maintain a pH level between 6.8 and 7.5.
Check ammonia, nitrite, and nitrate levels regularly to keep the system balanced.
Perform partial water changes if needed, especially in new systems.
Check out the video below to learn more about the benefits of using goldfish in aquaponics systems:
How Goldfish Help Plants Grow
Goldfish are more than pretty, they’re functional! Here's how their waste supports your plants:
Fish produce waste rich in ammonia.
Beneficial bacteria convert ammonia into nitrates.
Plants absorb nitrates, keeping the water clean for the fish.
Clean water cycles back into the fish tank.
Best Plants to Grow with Goldfish
Because goldfish aren’t raised for eating, most growers use them in systems for herbs, leafy greens, or decorative plants.
Try these beginner-friendly choices:
Leafy greens – Lettuce, spinach, bok choy
Herbs – Basil, mint, parsley, coriander
Strawberries – Thrive in goldfish systems
Houseplants – Pothos, ferns, and peace lilies for decorative setups
Common Aquaponics Mistakes with Goldfish (and How to Avoid Them)
Steer clear of these common issues when setting up your goldfish aquaponics DIY system:
Overfeeding – Leads to dirty water and unhealthy fish.
Overstocking – Too many fish can overwhelm a small system.
Ignoring water parameters – Regular testing ensures system stability.
Using chlorinated water – Always dechlorinate tap water before adding to your system.
Goldfish Are the Perfect Aquaponics Companion
If you’re just getting started with small-space aquaponics, goldfish are a reliable, low-fuss option to build confidence and see real results. They’re affordable, easy to care for, and create the perfect nutrient base for your plants.
Whether you’re growing herbs on your balcony or starting a full DIY system in the backyard, goldfish make aquaponics accessible, and fun, for beginners.
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 gardening option for you
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
Want to help out 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.
