Full Idea
Sea-water is the purest and the most polluted: for fish it is drinkable and life-giving; for men, not drinkable and destructive.
Gist of Idea
Sea water is life-giving for fish, but not for people
Source
Heraclitus (fragments/reports [c.500 BCE], B061), quoted by Hippolytus - Refutation of All Heresies 9.10.5
Book Reference
'Ancilla to the Pre-Socratic Philosophers', ed/tr. Freeman,Kathleen [Harvard 1957], p.29