Today I learned on this website about the existance of aquaponics. It sounds interesting, combining fish and vegetables.
Certainly! It's a synthetic pond ecosystem, optimized for growing that which humans care about (protein and plants).
But what I don't find on the internet is why we should do it.
I can't speak for other people. I can only speak for why I am quite interested in the concept and plan to "go big" with it in a few years (the raised bed gardens are a higher priority for next year).
I'm planning on setting up a moderate greenhouse devoted to aquaponics, mostly for the ability to grow my own food (beyond just vegetables), and to have the knowledge to scale that production if needed.
I'm rather less optimistic about the future of the system we live in than many people here, and so I've been working towards an "early retirement through self production of many necessities" path, moreso than "put it all in index funds." This means solar, gardens, tools, skills, etc. Call it homesteading, call it what you will. But, for me, a system capable of growing a lot of both fish and plants, in a dense system, year round? Very valuable to me.
Is it fun to grow some vegetables and some herbs above fish?
Better than having to filter the fish tank water regularly?
How big does it need to be to provide some food for yourselves?
Do you consider herbs food? Tiny. Do you want to make a dent in your grocery bill? Decently large.
Is it worth the cost and the hassle? I suppose the system needs warmth, light and fish food. I could image that for example the heating cost in the winter would be higher than the win on eating your own fish instead of food from the store.
That depends on how you design and build the system, and what you want to grow.
Tilapia are a popular option because they sort of shrug off system failures that would kill other fish. Koi are pretty good about that as well, and have the advantage of being worth a decent bit when grown (if you're looking for a cash stream).
Fish food, light, and warmth are certainly the requirements. Light is easy - just use the sun. Fish food can be somewhat expensive, depending on what you're growing, how. Tilapia have an advantage here as well in that they'll eat just about anything. You can toss kitchen scraps in and they'll chew it up. I wouldn't toss fish in, just because that's a terrible loop in terms of diseases and such, but other stuff? Sure.
For heat, I'm planning to do a rocket stove with substantial thermal mass, then probably propane backup. The primary heat will come from biomass - heat the rocket stove in the morning when needed, and heat the greenhouse and the fish water during the day on waste heat. If I can insulate it well enough to get a few days of low grade heat, so much the better.
I have a friend who raises tilapia (several hundred at a time) and is gettign into aquaponics. The biggest reason is that he must pay a steep fee to dump unfiltered water into the sanitary sewer. By using aquaponics to filter the water, he can reuse it and skip the fees.
Very nice! Yes, aquaponics solves the "flush the system" annoyances of both aquaculture and hydroponics quite nicely.
As far as hassle or cost, I'm not sure his setup provides any cost advantage to just getting it from the grocery store. However, the reason I buy his fish is because I know how it was grown, what it consumed for food and it is fresh, (i.e. I use dip nets to catch what I want) when I get it. If he scales up his veggie aquaponic test next year, I would definitely buy some from him but again, it probably won't be at a cost savings.
Knowing the source of your food seems increasingly important. Now that we've got a huge food company merged with a huge medical company, the incentives there are... perverse, at best.
I don't really expect it be cheaper than fish or vegetables from the store - just better, and radically more resilient.
