Heat a large Dutch oven or heavy-bottomed stockpot over medium-high heat, and then add the bacon and cook until crisp, about 8 minutes. Transfer to a paper-towel-lined plate and reserve.
Add the leeks to the remaining bacon grease and cook until softened and beginning to brown, about 5 minutes. Stir in the coriander, cayenne, potatoes, chiles and garlic. Mix until well incorporated and continue cooking until the potatoes start to brown, about 8 minutes. Once the potatoes are almost golden, add the wine, and using a wooden spoon, scrape up any bits that are stuck to the bottom of the pot. Cook the mixture until the wine has evaporated, about 3 minutes. Add 2 cups water, the orange juice, tomatoes and bouillon cube. Bring to a boil, and then reduce to a simmer, cooking until the potatoes are tender, 10 to 15 minutes.
Sprinkle the fish with salt and pepper, and then add to the soup and cook until the fish turns opaque and is cooked through, 4 to 5 minutes. Add the reserved cooked bacon, lime juice and taste, adjusting the seasoning with salt and pepper as necessary. Remember the bacon will bring plenty of salt, so taste before adding too much. Garnish the soup with fresh parsley and orange zest and serve in watermelon bowls if desired!