In a large cast-iron skillet, heat 1 inch of oil over medium to medium-high until a deep-fry thermometer registers 365°. Set a wire rack in a rimmed baking sheet.
Invert a small bowl in a large bowl. Place one corncob upright on top of the small bowl. Cut the kernels off the cob (they'll fall into the big bowl). Using the back of your knife, scrape to get the milky juice from the cob. Repeat with the other ears of corn.
In a large skillet, melt the butter over medium-high heat. When the butter foams, add the corn and its milk, the onion, celery, thyme, jalapeno and garlic; season with salt and pepper. Cook, stirring frequently, until the corn mixture is creamy, about 5 minutes. Just before serving, stir in the creme fraiche, remove from the heat and add hot sauce to taste.
While the corn is cooking, in a large bowl, whisk the flour, cornmeal, Old Bay and paprika. Add the beer, seltzer and vinegar. Stir until the mixture looks like thick pancake batter, adding more beer if needed to thin. Working with a few pieces at a time, coat the fish in the batter and fry, turning once, until cooked through and golden, 2 to 3 minutes per batch. Transfer to the wire rack to drain; season.
Divide the creamed corn among plates; top with the fish. Serve with more hot sauce and lime wedges.