Did you know you can grow your own fish to eat in your backyard and the fish will feed your vegetables? It's called aquaponics.
We get asked a bit about our Aquaponics setup and how we grow barramundi in our backyard so I decided I'd record a video of our setup. Full disclaimer, this is my husbands project (he studied marine biology and aquaculture) so I don't know the specifics of it exactly. This post is really to show what it is and our setup, not the ins and outs of how to do it.
What is aquaponics
A very simple explanation is you have a fish tank that is filtered by a grow bed that has vegetables growing in it. The fish feed the plants, the plants filter the water. Fish excrete nitrates that microbes can then convert to nutrients for the plants. We rarely have to add anything to the system for the plants and mainly need to keep the fish happy.
Our aquaponics setup
Our setup has evolved over time, you can see a few versions here. The most current system includes 4 grow beds (we need 6), 2 fish tanks and a sump.
The grow beds consist of a growing media called expanded clay beads. The plants are planted directly into this media. Within the grow bed is a bell siphon, water is run from the fish tanks into the grow beds. Once the water raises to a certain level the bell siphon activates and dumps the water into the sump. This allows air flow to the root plants so they don't become anaerobic.
The sump is essentially a holding tank for water that comes from the grow beds and the overflow from the fish tanks. We often keep crayfish or tiny fish in here, as the water fluctuates too much we can't use it as a fish tank. The sump sits below the grow beds and at a lower level from the main fish tanks.
We have 2 x 1000 litre tanks for our fish. We predominately grow barramundi (yes we need a heater over winter here in SEQLD) as we prefer to eat them and they grow fast. They can be temperamental though, we started with Jade Perch and they were very resilient (and don't need a heater). If you're looking at setting it up and you live in a different area you may find other fish do better. My dad had a setup in Tamworth NSW and had yellow belly and silver perch.
We can have around 25 fish in this setup but we have had more when they are younger (we've had up to 100 at one point which I wouldn't recommend). I believe the aim is 6 fish per grow bed. If you're not a fish eater you can grow ornamental varieties too just for fun.
Attached to the tank we also have an additional filter to help keep the fish happy. This is the part that we're looking at rejigging so we can get more sediment out of the fish tanks.
Is aquaponics right for you?
How much time do you have
In terms of the garden aspect, aquaponics is pretty hands off. There is no weeding, no watering and no feeding. Just plant and that's it. The fish and the water quality on the other hand do need regular attention. Obviously there is the daily feeding of your fish but also checking your filters and making sure they are happy regularly is important. The big one that gets us is being available to fix things when pumps die, the power goes out or a pipe breaks.
Whether aquaponics is worth the cost of running is debatable. The initial cost setup is probably similar if you are setting up raised beds and buying in soil, but you have to have your pumps running 24/7 and they do burn out so that's an ongoing cost. If you have solar power and energy is free then it's probably a no brainer, but it does need energy to run to ensure the fish are getting oxygen and survive.
I would only recommend it to someone who is looking for a hobby. Someone who is handy and can fix things easily. You will need to be interested in it, with time to spend on it. A garden bed can just be left alone when you don't have time and it's not a big deal. But when you're dealing with living things you need to feed and a lot of water it can become a problem if you don't have time to give it.
Check out our video here if you want a tour of our setup. Again, it's a work in progress and we're going to be rejigging it again soon which I'll show you when we finally get around to doing it.
I'd love to know if you are considering setting up aquaponics at home? Leave a comment below to let me know.