Hello dear i am 30 and i got into poultry around five years ago. I had to take a yr and a half break as i had a baby and have raised her and her twin brothers up a little bit but now i am able to restart. At that time i had gotten like minded that i wanted to raise poultry for an income. We lived off of my ex-boyfriends income but all the way full fledged my best month i drew 600$ after expenses. That was selling two goat kids, numerous chickens, chicks, quail, cages we had built extra for sale from scrap, going to someone elses house to proccess his birds and selling two tom turkeys too. At a differnt time i raised a bottle calf from auction i made a massive turn around from him by buying when stock yard prices were bottomed out dead of winter and selling in height of spring w prices sky high.
I want to encourage you that it can be done and no one here is trying to nay say they just need to be sure your expectations arent out of range. It would be difficult, but starting now while your so young and dedicated really gives you the best oppurtunity for success.
I think your numbers are on par for starting your aquaphonics system proccessing about 45 1 lb fish in your 300 gal tank. Be sure to test the water. Have you kept a freshwater indoor aquarium? If the water changes arent done to keep the ammonia down no amouny of filtration will work as the ammonia is the final product of the nitrogen cycle and it has to be cycled out without replacing All of the water which could cause a nitrate spike. The water should be cycled for a while before any fish are ever added. Theres more but im not sure if you know about freshwater aquariums. Ive looked into aquaphonics alot and its something im dying to try.