Rinse the fish fillet under running water and dry on a paper towel. Cut the fillets into 1/2-inch pieces. In a small bowl combine 1 tablespoon of olive oil, lemon juice, salt, and black pepper. Put pieces of fish in this marinade and roll well on all sides. Set the fishbowl aside.
In a large saucepan over medium-high heat, heat the remaining 1 tablespoon of olive oil. Pour onion, bell pepper, garlic, and chili into a saucepan, cook, stirring occasionally, for about 4 minutes. Then add chopped tomatoes and coconut milk, bring the mixture to a boil. Reduce heat and simmer without covering for about 10 minutes, stirring occasionally. Then put the fish in a saucepan with the marinade, shrimps and add 1/2 cup of cilantro, simmer, uncovered, for about 5 minutes, stirring occasionally.
Serve stews in portioned bowls with hot rice, sprinkle with chopped cilantro, and sprinkle with hot sauce (optional).