Climate change poses a severe threat to food production, making it imperative to find sustainable methods. One such method is aquaponics, which grows fish and vegetables together. Now, Ben-Gurion University of the Negev water researchers have offered a proof of concept for a new closed loop system that produced more fish and vegetables while using less energy than conventional systems.
This study describes further how that works:
https://phys.org/news/2023-06-fish-farm-biogas.html