The microFish Farm is a small recirculating aquaculture system (with a capacity of 600 to 1200 litres) characterised by a square fish tank and an overhead bio-filter.
It earns its place in our list of system layouts because it has been replicated many hundreds of times throughout Australia.
When we first developed the microFish Farm concept, several years ago, it was innovative for a number of reasons including:
- It was the first turnkey backyard-scale aquaponics system in Australia.
- It featured vertical stacking of components. The bio-filters were located on top of the tank which avoided the need for a support frame.
- Its compact footprint and efficient use of space.
- Its ability to be used inside or outside. In its second incarnation, it featured a long rectangular bio-filter that could also be used as a grow bed.
- It demonstrated that useful quantities of freshwater fish could be grown in as little as 600 litres of water.
- Its use of an access barrier – to keep toddlers, sunlight and predators out…..and the fish in.
- Its simplicity.
- Its capacity to be used in conjunction with a wide range of hydroponic and soil-based growing systems.
- Its ability to be disconnected from the growing system in the event of disease or infestation in fish or plants……or to minimise overnight heat loss.
A small submersible pump raises the water from the fish tank to an overhead flood and drain bio-filter. When the water level reaches a certain point an autosyphon is triggered unleashing a torrent of water back into the fish tank.
Our first microFish Farms were built from off-the-shelf components. We used 780 litre HDPE plastic bins (made for the horticulture industry to transport fruit and vegetables) as fish tanks. Recycled plastic barrels or stacking plastic crates (filled with oyster shells) were used for trickling bio-filters.
Fibreglass variants of the microFish Farm are also offered by two Australian manufacturers.
Where the movement of water through the overhead bio-filter is controlled by an auto-syphon there will be modest fluctation in the fish tank water level.
The microFish Farm can also be set up for continuous flow. Under this regime, the water level in the fish tank does not fluctuate.
If located outside, the overhead bio-filter can be planted out with seedlings, at which point the microFish Farm becomes a small aquaponics system.
A variety of other hydroponic growing systems can be added to the system – or the water from the fish tank can be used to irrigate soil-based food gardens.
Our 4 Tank system comprised (not surprisingly) four microFish Farms alongside of each other and provided the opportunity to trial different species and age groups.
While it suffers from some of the same limitations as other conventional aquaponics systems, the microFish Farm is both innovative and versatile.
Well managed, it is capable of producing plenty of clean fresh food.