A poor man, Pratinos was drawn to Kleon's talk of restoring Athens' glory, often gathering at rallies held by the Athenian general. Because of this, he and his friends, among them Aktis, were drawn into a plot to murder a statesman and a friend of Perikles, Metiochos.
When Metiochos visited the Fishing District, Pratinos, Aktis, and others hurled insults and rotten food at him. Later, they assaulted Metiochos in his home, tied him up and left him among snakes, provided by a man living outside Athens' walls. They thought themselves successful, until they met the Spartan misthios Kassandra, and learned she'd come to discover who was behind the attempt on Metiochos' life.
Pratinos gave up the location of the Poisoner, and Kassandra made sure the men would leave Metiochos and others alone in the future.
Sometime later, Kassandra met Pratinos' wife, who informed her that Pratinos had followed her advice.