In Hanafi madthab, it is haram to eat shellfish (lobster, crab, shrimp, oyster, etc.) In Shafi'i and Hanbali, everything from the sea is halal. In Maliki, everything but the eel is halal. In more clear words: Water-game and Sea-food is made lawful to you. read more
I think crab isn't forbidden, but if you look to what people do with the crab when they prepare it, it is horibble cause they boil the crabs alive. read more
In Hanafi madthab, it is haram to eat shellfish (lobster, crab, shrimp, oyster, etc.) In Shafi'i and Hanbali, everything from the sea is halal. In Maliki, everything but the eel is halal. read more