Make sure you keep the heat at medium low, so that everything gets fried evenly.
If you wish you can add any other cooking oil, using coconut oil gives authentic taste and flavor.
Adding curry leaves before frying will give a nice aroma and fish will not stick to the frying pan.
Try to use freshly ground black pepper; to make freshly ground pepper, fry the peppercorns in a hot pan for couple of minutes and grind it to a fine powder in mixier or in coffee grinder.Store this powder in an airtight container for later use.