Fish are not typically as picky about flies in open water, as they seem to be more opportunistic when ranging in the open ocean. Of course, if you see baitfish or squid jumping from the water as fish feed or if a fish you catch spits out some prey, you can tell what length and color they are and that’s the best place to start. Remember, it’s not the hook size that matters in saltwater flies, it’s the length. That why all saltwater flies you see listed on the Orvis website have both hook size and length stated. Most salt water flies incorporate a lot of white. Sometimes it pays to go to a color than what the fish are feeding on. For instance, few things in nature are fluorescent chartreuse, but that’s one of the most productive colors for saltwater flies. In low light, black is the actually most visible against the surface. In early morning, late evening, and at night, black flies are very popular.
Almost as important as size in saltwater flies is the shape or profile of the fly. Some baitfish, like sand eels or needlefish, are long and skinny. Some like Silversides and Anchovies are medium bodied. And fish like Mullet and Herring are very deep bodied. It helps to match the profile of the prevalent baitfish when choosing your flies. Surface flies are a blast in salt water, because you can see everything that happens and strikes are dramatic.