Well, yes it can be medium rare but this depends on how long you want it to cook for. Cooking time also depends on how thick your sea bass is. For medium rare fish, cook it for 4 minutes per side. You can tell if it’s done by making sure that it’s not pink in the middle and that the fish flakes when you press on it with your finger. You could also use a meat thermometer to test if it’s done. If it reads 140 degrees Fahrenheit or higher, then it’s done. If it’s not done yet, keep cooking for another minute or two and test again. If you think that it’s not cooked yet, then leave it to cook for another 3 minutes or so and check again. However, if you want your sea bass cooked well done, then cook it for about 6 minutes per side. This is only recommended if you’re cooking very thick sea bass fillets. It can be done with thinner fillets but they may need more time to cook through. You could also try grilling your sea bass on your gas grill instead of charcoal grill. If you don’t have a gas grill, then you can try baking your sea bass instead. To bake your sea bass, preheat your oven to 350 degrees Fahrenheit and line a baking sheet with aluminum foil. Place your sea bass fillets on the baking sheet and season with salt and pepper.