Yucatecan Grilled Catfish with Pickled Red Onions Recipe - Authentic Yucatan Dish

Ingredients

• 1 qt (946 ml) water, plus more as needed
• 2 small red onions, sliced 1 inch thick
• 2 tsp sugar
• 1 tsp dried oregano, preferably Mexican
• 0.5 tsp freshly ground pepper
• 0.5 tsp ground cumin
• 0.5 tsp salt
• 4 garlic cloves, halved
• 0.67 cup cider vinegar or lime juice
• 1 tbsp achiote seed (see note)
• 1 tsp freshly ground black pepper
• 1 tsp ground cinnamon
• 1 tsp ground coriander
• 0.25 tsp ground cloves
• 5 large garlic cloves
• 3 tbsp cider vinegar or lime juice
• 6 U.S. farm-raised catfish fillets
• olive oil for brushing