You can always plank fish. Several woods are available. On first use,the plank can impart a pretty strong flavor. However on second and third cooks the flavor calms down and imparts a very nice flavor. If you do an indirect cook the plank will last longer. You can put the plank on something like a pizza stone, or on my Big Green Egg a plate setter, and the plank will last longer. We did planked cod (fresh from Cape Cod) last night on an older cedar plank and it was wonderful - light smoke and cedar tastes. You can use cedar shingles as long as they have not been treated with anything, just be careful. Creosote or other treatment is not a good taste.