What type and where is the FOOD at the time one's there looking for them. Each body of water tends to be unique in the where, when and why they are where they are. Daytime, generally look for deeper water off a weedy flat/cove and often come across fish at the depth of the deepest weed growth. Night, just off the same weeds on the flat/cove and if one comes across a good sized fairly open horseshoe shaped area, it's worth a good lengthy shot. Area can be 5-20+ ft deep with them usually about half way, or more, down and looking up, but have had them come in with either their belly on the bottom or back scraping the ice. They tend to roam, you could be in the right place, just the wrong time. Not uncommon to catch a few, they circle off and then come back 10, 15, 30+ minutes later.