Have a look at the new Aquaponics option.
This is Fish -------> Vegetables -------> Goats or Chickens.
The old Fish water is used for the Vegetables.
Vegetables not sold or used are fed to the Goats.
Goat manure is fed to the Fishes and also used for the Vegatables.
This is very basic, and I am busy with a detailed Business Plan in this regard.
I don't only prepare Business Plans on request.
If I see an opportunity like the above, then I do research and sell the Business Plan where I see the need.