Fish! And of course crayfish/crawdads. These are the main products of the region, and whether you eat the fish barbecued, fried or smoked, it will be delicious. The crawdads with a beer are excellent as well. The Harsnaqar hotel complex near town has some unbelievably good crawdad kebabs, which aren't cheap, but might be worth splurging on.
There are some fast food place in town, and cafes, but most of the good places to eat are on the shores of the lake, a bit north.