I have been trench composting fish carcasses in my garden beds for 8 years. I alternate back and forth so every two years each bed gets between 5-800 pounds of fish carcasses. I hot compost on top of the bed and that absorbs any odors from the fish. Bumper crop of super tasty tomatoes every year. No synthetic fertilizers, pesticides, or herbicides.
I turn this...
Into this...
I turn this...
Into this...