Sand Lance Fish (also known as sand eels) is one of the favorite foods of the striped bass. They are not true eels, but their tube-like bodies and small fins give them an eel-like look. Biologically, they are more kin to silversides and anchovies than eels.
In the Northeast United States, look for these fish in early summer, particularly at dawn and dusk, in low water. They blend in with the background very well and are hard to pick out. Cast your fly line over them, however, and these nervous little guys will leap out of the water in fright. The sand eel is about 2 to 3 inches long, with a dark-green back and bright silver sides. You will find them in large schools on sandy beaches, in heavy surf, and in estuaries. At night, they slither into the sand to rest.
When you notice a school of these sand lance fish / eels, sink an eel imitation (something long, thin, and wiggly) alongside or below the school itself — the fly will look like a straggler, and stragglers get picked off. If you don’t see schools, look for bird activity or fish activity on the surface and cast to that. Strip your line in slowly but with a regular jerky action. In a fast current, you can vary the presentation of the fly, letting it drift along and occasionally twitching it.
At night, on calm water, try a surface or barely subsurface fly with a slow retrieve. Sometimes, you may see striper tails sticking straight out of the water. These are fish rooting around in the sand, trying to stir up sand eels. Let your fly sink and strip it slowly — you have to get it right next to the fish’s nose or he won’t see it.