I specialize in Outdoor backyard scale aquaponics systems using flood and drain media beds for filtration and plant growing space. There are plenty of other methods and I’ve been experimenting with some of them as additions to my current backyard systems. Since I have minimal experience with the other methods, I’m not willing to comment much on them. I will attempt to stick with sharing what has worked well for me along with explanations about why I think it has worked well. I also share what hasn’t worked well for me and why.
Keep in mind I’m in a nearly sub-tropical climate but inland enough that we can get hard freezes (periods of more than a few hours well below freezing.)
For those who wish to learn for themselves step by step, I often recommend reading The Barrel-Ponics Manual by Travis W. Hughey Free PDF
It is a good primer for building and plumbing of a small system though I’ve never done well with a barrel as a fish tank and would probably sub in a different fish tank. A barrel ponics system will only support a small number of fish perhaps start with 8 small tilapia or 5 of most other types of fish.
I personally like much larger fish tanks and for my climate in a stand alone system, I recommend a minimum size fish tank of 300 gallons. This is big enough to provide some temperature stability and big enough to grow catfish out to a nice size. I’ve tried smaller fish tanks for fingerling or quarantine systems and have never had good luck with them. Catfish only seem to do well in a small tank when they are really tiny. Even a 100 gallon tank only worked well for me with really small fingerlings.
So, for a nice backyard home aquaponics system I will recommend (at least outdoors in my climate) a minimum size of 300 gallons of fish tank with at least 300 gallons of grow beds to start. I actually really recommend 600 gallons of flood and drain gravel beds but that will either require a sump tank or an Aquaponics indexing valve. Currently I have a 300 gallon tank hooked up with 3, 100 gallon stock tanks as grow beds. That system has 30 small catfish in it and is near it’s limits for a first year system. If we want to grow the fish much larger, we will need to harvest and eat a bunch of them small to let the others grow.
My plan is to add another three 100 gallon stock tanks to this backyard home Aquaponics system. It already uses an indexing valve that will allow me to add three more beds simply by changing the cam and adding the plumbing to them. Come the end of the year, this 300 gallon tank will have 600 gallons of flood and drain gravel grow beds supporting it and I should be able to grow all 30 of those fish out to a nice size.