AtD translation: kippers and bloaters

[Mike Jing]

P605.1-7   One morning Lew walked into the breakfast parlor at Chunxton
Crescent to find Police Inspector Vance Aychrome, angelically revealed in
early sunbeams through the stained-glass dome overhead, relentlessly
despoiling a Full English Breakfast modified for the Pythagorean dietary
here, including imitation sausages, kippers and bloaters, omelettes, fried
potatoes, fried tomatoes, porridge, buns, baps, scones, and loaves in
various formats.

Are these "kippers and bloaters" real fish or imitation as well? Is fish
allowed in the Pythagorean diet?

Note that there is also a mention of "Yarmouth bloater" on page 608.