I know it is very appealing to think you can create an aquaponics system to give you weed and fish to eat, but that is not the experience of commercial aquaponics growers. You really get very few fish out of it, and your existing fish are more valuable as nutrient makers than as food. The commercial growers in Hawaii make money off their gourmet organic lettuces they sell to fancy restaurants. They don’t make anything off their fish.
You can grow good weed with it, and if you had a way to sell it, the whole thing could more than pay for itself off the weed crop. But I’m not sure it would be economically competitive with just buying nutrients in bulk.
I’m a systems ecologist by education and my wife did a graduate degree program in aquaculture and fish pathology, so I am not just pulling this out of my butt.
If you are going to do it, do it for a hobby because if you try to scale it up into a business you will probably go broke.