We converted a dairy barn in Wisconsin to fully indoor (no outside light, light dep by today’s standards) Nelson Pade aquaponics system.
4x 250 gallon talapia tanks feeds (no devils) lettuce to three schools in the local area.
We grew a hemp plant (cherry wife) to flower in 2017 on 2-400ppm. He wasn’t supposed to grow it, but we had space to drop in a plant so we just went with it.
So I can say it totally works, but those systems are quite complex with all the equipment and filtration for a closed loop cycle. Pretty expensive, like a $250,000 install. Haven’t seen anyone grow cannabis plants commercially from talapia yet using Nelson pade aquaponic systems. Would love to see it happen!
Edit: wanted to add that it takes a lot of (properly managed) fish to poop and make high enough ppms for the nutes to matter.