Press redfish down on one side onto your favorite blackening seasoning and sear on medium-to-high heat. Cook for 2–3 minutes on each side.
In another pan, heat olive oil on medium heat. Smash garlic and roughly chop; add to oil. Add spinach, season with salt and pepper and sauté.
Roll potatoes in olive oil and salt and pepper. Cook at 350° for 18–22 minutes until fork tender.
Add sautéed spinach to plate with roasted potatoes, top with redfish and serve.