You could try out planks, but with the price of most fish nowdays, that bumps up an already fairly expensive meal......
I use planks over direct heat, after a goodly soak in water...............heat one side of a blank plank for a few minutes, turn over, add fish, go for a short time (plank will also give you a bit more leeway than straight on the grates) & done.............
The other way fish works well is 'baking' / semi-grilling indirect......
Some of the folks on here are real good at grilling direct (OTPlatinum, Duke & others come to mind)
but I tend to foul up a hi-heat deal on fish & so elect for a safer route of a medium heat indirect cook & usually goes pretty reasonable......more time to catch a runaway mistake about to happen also.....if you get in a situation like you were fixing up other stuff...............