The easiest way to catch a big fish on a fly is on a streamer, a wet fly that imitates a small baitfish that larger fish feed on. If you can cast 20 feet, you can catch fish in streams and rivers on a streamer. You can even strip line off the reel and into the water and let the fly drift in the current and catch fish. The line swims the fly, making it look like a swimming baitfish.

Cast a streamer such as a Woolly Bugger into moving water and you can expect a strike from a hungry fish. To improve the action, attach a split-shot to the leader just ahead of the fly and give the rod tip a bounce now and then as the streamer drifts downstream. The bounce of the tip causes the fly to jig up and down like a wounded minnow, and all gamefish are hunters for wounded baitfish.

Big saltwater or freshwater streamers require bigger rods to cast; 7-weight, 8-weight, or larger rods. The larger the fly, the larger the rod you'll need to cast and fight the fish (small flies can also catch large fish).

When fishing streamers, first ask yourself: Which baitfish do the larger fish feed on? For instance, if you're fishing for bass in a stream and the bass feed mostly on crayfish there, then you'll need a fly that looks like a crayfish. But if silver-colored minnows are their main food then you'll want to use a silver minnow streamer.

While the fly line will swim the fly in moving water, it will not swim it in the still waters of ponds and lakes. You have to swim the fly by casting and retrieving the fly. The farther you can cast, the longer your retrieve of the fly and the more fish you'll catch.

Different lines retrieve the fly at different levels in the water. For instance a floating line will fish and retrieve the fly near the surface. But if the fish are deep, you need to get the fly deep to catch them. You'll need a sinking line to get the fly down to the fish.

Sinking lines are heavier than water. The heavier the line, the faster it sinks. In deep water or fast-moving water you need a fast-sinking line to reach bottom with the streamer. In slow-moving shallow water you need a floating line. On lakes an intermediate line is excellent for fishing streamers below the surface.

Fishing a streamer in ponds or lakes is simple--cast and retrieve it with a slow hand-twist retrieve or simply let it swing and follow behind the boat or float-tube as you move. The fish will do the rest.

In streams simply cast the streamer across the current and let the flow take it downstream. Most of your strikes will happen at the bottom of the swing. Cast the streamer toward the bank when fishing from a boat and retrieve it fast. Bass and trout will leap on it.