What is the reason that Hanafis cannot eat seafood?

Specifically in the Hanafi Madhab, only that which is considered to be fish within the sea will be permissible because the Prophet Sallallahu Alaihi Wasallam and the companions were known to have eaten fish. Now the majority of scholars, they extend it, and based on various hadith as well, to say that it means anything within the sea, generally speaking. But the Hanafi Madhab specifically restricts it, based on these hadith that the Prophet Sallallahu Alaihi Wasallam ate fish only, to only being fish, which is that which is permissible.