

You are correct
Its a tomte or vätte, most commonly translated to goblin but more similar to house spirit. Impregnerad is the swedish word of “impregrated by something”, used about tent cloth, boots or other items, very rarely about creatures where the words gravid or havande is used.



Its a catholic thing so they can eat fish on days when they abstain from meat
https://www.britannica.com/topic/Why-Do-Catholics-Eat-Fish-on-Fridays