It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that some people came to the presence of the Prophet (peace and blessings be upon him) and asked: "We travel by sea and carry only a little water for drinking. If we use it for ablution, we will be left thirsty. Can we perform ablution with sea water?" The Prophet (peace and blessings be upon him) replied: "The water of the sea is purifying and its dead (fish) is lawful."