1. Salmon – Using skinless salmon means more exposed flesh, so the butter will seep in better into the salmon flesh. But it’s really not a big deal if you only have skin-on salmon: Start cooking skin side UP, then flip and start basting with skin side is down.
Other fish – You can use this method of cooking for any fish suitable for pan frying.
2. Internal temperature of cooked salmon:

3. Leftovers – Cooked salmon keeps for 3 to 4 days in the fridge. Gently reheat in oven or microwave, or use flaked at room temperature in salads, sandwiches etc.
4. Nutrition per serving, assuming all the butter is consumed.