(Sometimes called the Gilli-Galoo Fish)
Piscisabsurdus tumescens
A tasty fish, found only in perfectly round lakes. Hence quite rare. To catch him, row to the exact center of the lake, using the hogyoke to determine position, and bore a square hole in the water. Bait the edge of this hole with a bit of cheese, preferably Brie, Stilton, Liederkranz, or best of all; Limburger. The Whiffenpoof will quickly scent the bait and come for it. When he emerges, spit tobacco-juice in his eye. This will make him so swell with rage that he won’t be able to withdraw into the hole, and you can easily net him.