I smoke a LOT of trout, and I do not use a water pan (I do use one for most other smokes, though). I hot smoke (225 - 250*) for 1.5 - 2 hours until the fish flakes with a fork. This produces a slightly dry texture which we prefer. (This is really great on crackers with cream cheese!) Water pans generally help keep temps stable and keeps the moisture level up during long smokes. I butterfly the trout, salt & pepper and place on the grate skin side up (unless fileted).