A community-led "fish allotment" scheme to farm fresh fish and vegetables in the city is being trialled in Bristol.
The aquaponic farm, a variant of the water-frugal plant-growing technique hydroponics, has been set up by the Bristol Fish Project in Bedminster.
Volunteers are being offered free or "cost price" fish and green vegetables in exchange for working on the project.
Alice-Marie Archer, project founder, said the five month trial is to "find out if an urban fish farm is viable".
Aquaponics is designed to farm fish and plants together in a space-saving "closed ecosystem" using a minimum of water.
Fish waste provides the nitrates and phosphates for the plants to grow and the water is returned back to the fish tanks as part of a closed water system.
Work on Bristol's "demo" farm began in May with a start-up cost of about £3,000.
Housed in a polytunnel, it has more than 80 tilapia hatchlings held in two 1,000 litre fish tanks feeding plant beds of leafy greens.
"We've chosen tilapia as it's very hardy and easy to farm, supposedly, and people will readily eat them," said Ms Archer.
"Carp can also be used but people don't tend to like the taste of it.
"And we have two really massive fish tanks at the moment but we will need to add another four to accommodate the growing fish."
The first "crop" of tilapia is expected in February while the fast growing leafy greens are expected to be harvested within a couple of weeks.
"It's pretty intensive at the beginning, testing the water and keeping the equilibrium of the system, but it should get easier as it settles over the next couple of weeks," added Ms Archer.
"And we're hoping, at the end of the trial when we evaluate it, we'll be able to carry it on and expand it."