Frozen cod or other fish can be used in place of fresh cod.
Slice up the celery, and in a pot put the undrained tomatoes, celery, oregano, basil, salt, and pepper. Bring to a boil over medium heat.
Place the fish fillets in the pot. Reduce the heat and cook for 5-10 minutes, or 10-15 if using frozen fillets. Continue cooking until the fish is opaque and flaky and the mixture is heated throughout. Optionally, thin the mixture with water.