Season the fish fillets with salt, pepper and Cajun seasoning. Lightly dust the seasoned fillets with flour and set to the side.
In a heavy-bottomed skillet over medium heat, melt the stick of butter, reserving 1 tablespoon. Sauté the prepared fillets in the butter until brown, 2 to 3 minutes per side, flipping only once.
Remove fillets to a plate, then add the remaining tablespoon of melted butter to the pan. When the butter begins to foam, add the almonds, cooking until toasted. Add the lemon juice, stirring until fully incorporated; taste and adjust for seasonings.
Pour almandine sauce over fillets.
Serve.