Do you love big bluegill?
You'll need to do your own research, bu I doubt you can propagate the species in a single tank environment. Bluegill go cannibalistic after the nesting phase. You'll need a separate tank for the fry, or they're LUNCH! Try placing round gravel faced path stones with a sand coating during spawn, and moving them [GENTLY!] to a separate, smaller tank. Fry will school, to a point about 7 days after hatching. That's when the parents scarf them up, and they run for cover. Survival of the fittest! It's the nature of the beast... bream are excellent predators!
Remember that protein added to the system increases PH. Protein is necessary for growth... so without serious filtration, you will never keep your fish alive, much less harvest a good fish fry. Hydroponic ebb and flow systems offer excellent water filtration, while producing a separate crop. You'll need a greenhouse environment, but a gravel bed table can grow culinary herbs like lemon grass or sweet basil... both are very marketable! Keep the green crop in synchronized with the fish crop: they are a balanced system, and cannot survive major losses on either side. It's important to keep planting MORE as the fish grow.
I've got extensive college courses on aquaculture and hydroponics, and I'd be happy to advise you in the design of a circulating system. Take me fishing... or send me a box of frozen fillets, and money for wine!
I love these type systems... they're tricky, but when they work, it's like POETRY!
All of this points out why people usually use some other fish for captive systems - tilapia, for example.
The high school FFA program raises those in a livestock tank, in a class room! Very little management, per se.
Tilapia are a great aquaculture fish: filter feeders keep their own water "clean". Here in the south a lot of catfish farmers will add them to the ponds as a sort of "swimming filter", which allows them to stock catfish at higher densities. The same trick would probably work well with BG... if they didn't kick the tilapias butts!
Remember that plants can be foliar fed. Spray the leaves well with a balanced fertilizer, they will absorb it quickly, and there's no need to spike the water... which is always risky for the fish! "OFF" tastes can result, even if the fish seem not to mind. You can use benthos [bottom feeders] like crayfish or snails, to absorb fish wastes, if you can keep the fish from eating them. There are some excellent resources online, and a lot of great ideas flying around... so let us know how you decide to do it! This could be very cool! I don't have space for a greenhouse... but you've got me thinking of fattening up a couple coppernose in a home made tank... I bet I could think up a system that would work!
How's your program going - any tank spawning this year?
Lost all 36 BG due to losing my pump and therefore my source of oxygenation for the water. relocating the whole aquaponics system before I try again. They were getting big too. Was just about to set up the breeding tank and move a few of them over.
Bummer. I installed a second pump with battery backup for aeration only in hopes of avoiding something similar. Plan for the worst and hope for the best is a saying I've read on the subject. Good luck.