Heat olive oil in a large pot over medium heat. Add celery, carrots, onion, and garlic to hot oil; cook and stir until onion is tender. Add water, tomatoes, wine, clam juice, sherry, and bouillon; stir until bouillon is dissolved. Season with red pepper flakes, salt, and pepper. Bring to a boil, then reduce heat to low and simmer for 1 hour.

Stir in shrimp, fish, and cilantro. Continue cooking until shrimp is opaque and fish flakes easily with a fork, about 5 minutes. Remove from heat and let sit for 10 minutes before serving.