It’s fish. Right? They live in the water.
1.xxvi. Item beaver tails and odr visch (‘the other fish’?), as they are called, (are) roasted well, with ginger strewed on them and served warm. But if you would boil them, a pepper sauce (pfefferlein) made (to pour) over them is good, or a sauce (ziseünlein) made with gingerbread and well pounded pepper strewn on it.
My current project are recipes from the Nuremberg Kuchenmaistrey produced around 1490. This was the earliest printed cookbook in German (and only missed being the earliest printed cookbook in any language by a few years). The Kuchenmaistrey (mastery of the kitchen) gave rise to a vibrant culture of amended and expanded manuscript copies as well as reprints spanning almost a century. The recipes seem designed to appeal to a wealthy, literate and cosmopolitan clientele.