Store-brought smoked salmon is a hit-and-miss affair; it is sometimes hard to tell a good product from a bad one, because it is impossible to know the quality of the fish that was used for smoking or the quality of the other ingredients. When making your own, you have control over all these elements, and the result is always excellent. You can use ocean trout or other fish, but you need to make sure you alter the curing time to the size of the fillet. It is hard to specify an exact time frame, because the thickness of the fish dictates the time it takes. The rule of thumb is that, when it is ready, the fish should be quite firm in the fattest part.