Ecologist Rodney Ingersoll said fish, while not the best company, can more than earn their keep.

About six years ago Mr Ingersoll converted his backyard into a unique living biological system, using the sustainable method of aquaponics to grow fruit and vegetables.

Aquaponics combines features of hydroponics and aquaculture - or fish farming - in a process that enables plants to grow in a weed-free, low-maintenance environment.

Mr Ingersoll feeds his family year-round with organic produce, thanks to the help of more than 250 fish.

"I have trout, gold fish and silver perch, as well as yabbies," he said.

"I feed the fish and the fish feed me," Mr Ingersoll said.

Mr Ingersoll's aquaponic system was developed using trial and error.

In the past six years, he has created more than 10 different systems, but has settled on using an old children's pool and existing fish pond.

A pump and siphon in the middle effectively drains and waters both the plants and fish.

Mr Ingersoll said he could "just set and forget".

"It just goes to show what you can do with recycled things around the home," he said.

"You minimise waste and damage on the planet, and anyone can have this system in their backyard."

Go to aquaponicgardener.com.au for more information.