Preheat your oven to 400 degrees.
Your fish will need to have its insides and all scales removed (have your butcher do this). Rinse the fish and pat dry.
Rub the outside of the fish with olive oil (so it will be easier to remove the salt crust after it bakes). Stuff the fish with your favorite aromatics- herbs, lemons, garlic, shallots- whatever you like!
Next, mix your salt with the egg whites and water. Spread enough of the salt mixture on the baking pan to make a bed to put the fish on, about 1/4” thick. Put the fish on top of the salt bed and make a 1/4” crust around the entire fish.
Roast the fish for 20-30 minutes of until an instant read thermometer reads 135 degrees.
Remove the fish and let it rest for 5-10 minutes.