Q: Are shell fish such as clams, mussels, oysters, scollops, etc halal?
A. A Hadeeth specifies two things that can be eaten without slaughtering. One of them is fish. This Hadeeth specifically mentions the word 'As Samak' which means fish. The Hanafi jurists, citing this Hadeeth, say that only that is Halaal for consumption from the sea which falls under the category of As Samak. This discussion is lengthy and technical and can be found in the Arabic books of Fiqh. The above is the gist of the discussion. (Raddul Muhtaar V26 P193, Kashful Khifaa V1 P59, Al Mabsoot of Imam Sarakhsi V11 P398)
The items you mentioned do not fall under the category of fish (As Samak). (This is according to the Hanafi Madhab).
Allah Ta'aala knows best.
Moulana Yusuf Laher
Checked by: Mufti Siraj Desai