สัญลักษณ์ปลาThe fishΙΧΘΥΣ

The Christian fish is an acrostic before it is an animal. ΙΧΘΥΣ spells out Ἰησοῦς Χρῑστός Θεοῦ Υἱός Σωτήρ — Jesus Christ, God's Son, Saviour. It appears in Christian art and literature from the second century CE and is widespread by the late second to fourth. It is found in the Catacombs of Saint Sebastian and the Catacomb of Priscilla, in the marble ruins of Ephesus, and on funerary stelae carrying inscriptions such as ΙΧΘΥϹ ΖΩΝΤΩΝ, fish of the living.

The story most people have heard about it is disputed. Robert Mowat proposed in 1900 that it was a secret sign among persecuted Christians, arguing from silence. Modern scholarship disputes that: Rasimus lists it among solutions that were once popular, and no early Christian source ties the fish to persecution. The connections the early sources do make are to baptism, to the Eucharist and to the feeding of the multitude.

The fish also turns up on a dated amulet with a word square on its back. The earliest Sator square with explicit Christian imagery is a sixth-century bronze amulet from Asia Minor: two fish turned towards one another on one side, the Sator square in Greek characters on the other, and ICHTHUS written above the square. It is in the Berlin State Museums.

China's fish is a coin. Among the shapes Chinese numismatic charms took as they separated from circulating coinage were spades, locks, fish, peaches and gourds, and fish and lock charms were worn mainly by young children and infants — daily wear rather than festival wear.

Inference — this atlas has not found a source connecting the Christian fish and the Chinese fish charm, and does not connect them. A fish is a common animal and an easy outline; two traditions reaching for it is not evidence of contact.