Peel the potatoes, and cut them into big even-sized chunks. Wash them and place them in a large pot with about a teaspoon of salt and enough water to cover them.
Cook until they're fork-tender. Drain the water, put the potatoes back on the heat, and simmer for about a minute to remove excess moisture.
Mash roughly with a fork and set aside.
Sprinkle fish with salt, pepper, and Creole seasoning.
Mash roughly with a fork and Set aside.
Add oil and butter to a skillet and cook the fish for about 4 minutes. Be careful not to overcook it. Set aside.
Add onion and celery and sauté for about 2 minutes. Then add the garlic, green onion, and parsley, and sauté for 2 more minutes.
Pour the mixture into the mashed potatoes.
Gently mix in the fish, being careful not over-mash the fish or potatoes.
Scoop out ¼ cup of mixture and mold into a firm 2-inch patty. Place it on a tray and repeat until the fish cake mixture has been used.
Refrigerate the tray of patties for an hour.
Place the flour, egg, and breadcrumbs on separate plates.
First, coat the patties in flour, shake off the excess, and dip them in the egg. Then coat them with breadcrumbs.
Heat oil on medium-high heat in a skillet and cook fish cakes in batches for 2 minutes on each side until golden.
Transfer to a paper-towel-lined plate until all the fish cakes are done. Serve with tartar or remoulade sauce, and enjoy.