A Snippet about Marc and fish -- sort of

Someone asked for a snippet about Marc.  Note that many of the details here come from a medieval cookbook.  One can't make such things up.  This is set in Tagmeth.

Apprentices scurried about the keep’s kitchen, preparing the midday meal.  Off to one side, Marc was learning how to prepare lamprey soup.
“Now, I’ve taught you how to dress this slippery fellow,” the little master cook was saying, obviously pleased to have no less a person than the keep’s steward leaning attentively over him.  “Repeat.”
“First, you bleed it through the mouth and cut out its tongue,” said Marc, with the air of someone counting steps on his fingers.  “That last is to stop it from screaming.  Save the blood, for it is the fat.  Then scald it as you would an eel.”
“Yes!  And here it is.”
The cook thrust a long handled fork into a seething pot and drew out a dark, lank form, not unlike a boiled snake.
“Oh, what a beauty!” he exclaimed, turning it so that it flopped this way and that, its tongue-bereft circular mouth grimacing with rings of bared teeth.  “Caught it myself, I did.  I’ve never seen its like.”
Probably he hadn’t, thought Jame.  Such fish weren’t known in Kothifir from which, judging from his walnut tan, the cook had recently come.
“Then thread it crosswise on a very thin spit in one or two loops, like this, and roast it.  Meanwhile, what spices do you prepare?”
“Ginger, cassia, cloves, nutmeg, grains of paradise … what’s that, by the way?”
“Never mind.  We don’t have any.  If we had some parsley, we could turn the broth bright green, but it’s supposed to be thick and black.  ‘Mud,’ we call it.”
Jame regarded the sinuous loop crackling in the flames and seeming, stealthily, to writhe. 
“That’s not a lamprey,” she said.  “It’s a blackhead.”
The little cook blinked at her.  “A what?”
“They come from the lake that’s the source of the Silver, under the shadow of Perimal Darkling.  When they bite their prey, they lay eggs in its flesh.  These hatch and compel their host to migrate down-stream, even while they devour its flesh from the inside out. Finally it explodes, releasing them to a new stretch of the river.  I’ve seen them infest a man who ate an infected host.  It wasn’t pretty.”
As the cook stared at her, aghast, Marc reached over his shoulder and slid the creature off the spit, into the devouring flames.
“There, there,” he said, patting the little man kindly on the back.  “Why don’t you teach me how to make a nice parsnip pottage instead?”