Prepare the cod. Pat the cod dry with a paper towel.
Place 2 tablespoons of flour onto a plate, season the flour with salt, pepper, and cumin. Dredge the fish in the seasoned flour mixture until it's lightly coated. If you are gluten-free, you can sub corn starch or gluten-free flour, or skip the flour and season the fish without it. The flour adds thickness to the stew.
Heat a stockpot over medium heat and add olive oil. Add the seasoned cod to the pot and cook about 3 the fish minutes on each side, just until browned. Remove the fish from the pot and place it on a plate until later. Note - the fish may stick to the pan, but that's ok, just remove what you can and eave the remaining brown bits as they add flavor to the stew.
Add onions, garlic, carrots, and peppers to the stockpot and cook until translucent and slightly soft, stirring often for about 6 minutes. You can add extra olive oil if needed for this step. Add salt, pepper, cumin, and oregano and stir to combine. Add canned tomatoes and 3 cups of water (or seafood stock/vegetable broth) to the pot. Add potatoes to the pot as well. Bring to a boil, then reduce to a simmer.
Simmer for about 20 minutes until carrots and potatoes are soft, stirring occasionally. Add the cod back to the pot and cook for an additional 5 - 10 minutes for the flavors to incorporate. Zest a lemon over the pot and squeeze the juice from one lemon into the pot.
Taste for seasoning and add salt and pepper to taste.
Serve with a dollop of sour cream, Greek yogurt or quark for extra creaminess. Also, serve with lemons on the side for anyone who likes the extra lemon flavor.