Felchen is the fish of Lake Constance — a whitefish caught in the cold, deep water of the Bodensee and pan-fried simply, usually with butter and almonds or served alongside boiled potatoes and a wedge of lemon. It is delicate and clean, and it tastes of the lake. Hecht (pike) turns up in a more elaborate preparation, often as Hechtklößchen (pike dumplings) in a cream sauce.
Restaurants serving lake fish properly tend to be straightforward places without much pretension: paper tablecloths, a short menu, local wine. The Konzilstrasse and the streets leading down to the harbour are the best area to look.