Catching fish in a frozen lake isn't so different from catching them in the same thawed lake. The techniques may vary some, but in the end you're dropping bait or a lure into the water in hopes that a fish will clamp down and hook. But you'll want to fish deeper than you normally would in the other seasons. In fact, you'll fish near the bottom of the lake. The water in a frozen lake varies from about 32 degrees to 39 degrees. The "warm" water will be nearest to the bottom, and since fish want to be comfortable, too, they'll most likely be hanging out down in the depths.
If you're looking for a place to drop your hut and cut a hole, the old adage is: "Look for the other fishermen." This is true to a large extent. Chances are, if you see a cluster of ice fishing huts and folks are having a good time, that's a great place to set up shop. And in the United States, ice fishing is a social event, so other fishermen don't mind grouping together to spin a yarn or two while waiting for a bite.
The use of flashers is becoming increasingly popular as well. A flasher is the winter version of the summer lake "fish finder." It's a sonar system that provides information on depth and whether or not there are any fish swimming around the area -- a major upgrade from the old days when ice fishermen would simply sit over a hole and wait for the catch to swim underneath them. Flashers are able to render information in real time, as well as indicate the location of your lure or bait. This means that an ice fisherman can literally locate a fish beneath him and position his hook in the exact place most likely to catch the fish's attention. You'll be vying for the same fish that you would in the summer in these locations -- pike, crappie, sturgeon, perch and walleye, just to name a few.
WHY YOU SHOULD THROW IT BACK
Ice fishermen, more so than other types of sport fishermen, are less likely to practice catch-and-release. They're typically out for dinner, not a trophy to mount for the wall. For conservation sake, ice fishermen are encouraged to follow the local rules and ordinances that dictate how many fish can be kept, what size is allowed and how many different lines are used in a single hole. As long as ice fishermen follow the guidelines, fish taken from frozen lakes aren't in danger or threatened.