The dietary laws in Leviticus are very specific about seafood: only creatures with both fins and scales are permissible to eat. This makes popular menu items like shrimp, lobster, clams, oysters, and crab 'detestable' and forbidden for consumption. 'Whatever in the seas and the rivers that does not have fins and scales... is detestable to you.' — Leviticus 11:10 (ESV)
