Netiv Chayim on Shulchan Arukh, Orach Chayim Siman 552
Can copy this into an AI, or connect the whole library to your assistant. For deeper learning, you can directly use the original seforim, sites, and apps.
(במג"א סק"ד) אבל דגים. נ"ב לדוגמ' נקט דהא דגים בלא"ה נהגו לאסור: