How to Keep Fish in an Aquaponic System (Australian Climate Guide)

Running a successful aquaponics system in Australia comes down to choosing the right fish, preparing your water properly, and maintaining stable conditions year-round.

Whether you’re running a backyard system or a larger setup, this guide will help you avoid the most common mistakes and get strong results from both fish and plants.

What Is Aquaponics?

Aquaponics combines fish farming and plant growing in one system. Fish waste feeds plants, and plants clean the water, creating a self-sustaining ecosystem.

Best Fish for Australian Conditions

Australia’s climate varies, so choosing the right fish is key:

Warm Water (20–30°C)

• Barramundi

• Jade Perch

Temperate (15–25°C)

• Silver Perch (most popular in Australia)

• Golden Perch

Cooler Months (10–20°C)

• Rainbow Trout (great winter option)

• Murray Cod

In places like Melbourne, many growers switch fish seasonally (e.g. trout in winter, perch in summer).

How to Prepare Water Before Adding Fish (MOST IMPORTANT STEP)

Adding fish too early is the #1 reason systems fail. Here’s how to do it properly:

1. Remove Chlorine & Chloramine

Australian tap water contains disinfectants that will kill fish and beneficial bacteria.

• Let water sit 24–48 hours (chlorine only)

• Use a water conditioner for instant treatment

• Chloramine must be treated (won’t evaporate)

2. Balance Water Parameters

Before fish go in:

• pH: 6.5 – 7.5

• Ammonia: 0 ppm

• Nitrites: 0 ppm

Testing is critical—most aquaponic systems rely on regular water testing to stay stable.

Many complete systems at Urban Green Farms include test kits so you can prepare ad monitor water easily from day one.

Freshwater Master Kit

A$80.00

Buy Now

3. Cycle Your System (Build Good Bacteria)

Aquaponics relies on the Nitrogen Cycle:

• Fish waste → ammonia

• Bacteria convert ammonia → nitrites

• Bacteria convert nitrites → nitrates (plant food)

Best Method: Fishless Cycling

• Add ammonia source

• Run system 2–4 weeks

• Wait until ammonia & nitrites = 0

This step ensures your fish won’t be poisoned when introduced.

550L Aquaponic Farm - Package One

A$3,499.00

Buy Now

4. Stabilise Temperature

• Match water temp to your fish species

• Avoid sudden changes

• Use shade (summer) or heaters (winter)

5. Add Aeration

• Use air pumps and stones

• Warm Australian summers = lower oxygen → increase aeration

Adding Fish Safely

Once your system is cycled:

1. Float bag for 15–20 mins

2. Slowly mix tank water

3. Release fish gently

Start with low stocking levels and increase gradually.

pH Pen Meter

A$48.00A$43.20

Buy Now

Ongoing Fish Care

Feeding

• 1–2 times daily

• Only what fish eat within a few minutes

Water Testing

• Weekly checks:

  • pH

  • Ammonia

  • Nitrites

  • Nitrates

  
  

  Urban Green Farms provide maintenace checklist to every Aquaponics Farm customer to support you on your journey.

  
  

Maintenance

• Remove uneaten food

• Check pumps and airflow

• Watch for signs of stress

pH Down- API

FromA$11.00

Buy Now

Managing Australian Weather

Summer

• Add shade cloth

• Increase aeration

• Reduce feeding in extreme heat

Winter

• Use cold-tolerant fish (like trout)

• Feed less (fish metabolism slows)

Using a Complete Aquaponics Kit (Recommended for Beginners)

Starting from scratch can be tricky, especially when it comes to water quality, cycling, and system balance.

Systems like the Aquaponic Farm Kits from Urban Green Farms are designed to simplify the process by including key components such as:

• Water testing kits

• Fish Food

• Pumps, filter bags and aeration

• Growing media and plumbing

• Starter inputs for cycling

These kits are built to create a balanced ecosystem from day one, helping reduce beginner mistakes and setup guesswork. Many systems include everything needed to get started—just add fish and plants.

Complete STEM School Aquaponic Learning Bundle

A$6,699.00

Buy Now

Common Mistakes to Avoid

• Adding fish before cycling

• Not removing chlorine/chloramine

• Overstocking too quickly

• Overfeeding

• Ignoring temperature swings

Final Tip

Aquaponics success is all about stability, not speed. Take the time to prepare your water properly, and your fish and plants will thrive together in a self sustaining automated system.

To Learn more about aquaponics Urban Green Farms offer FREE Online Courses.