Leviticus 11:9-11:

You may eat anything that lives in the water—that is, you may eat anything that has fins and scales either from the seas or from the rivers. But anything that doesn’t have fins or scales—whether from the seas or the rivers—any of the swarming creatures and living creatures in the waters are detestable for you. They are to remain detestable for you. You are not to eat of their meat and you are to detest their carcasses.