Yellow gold necklace composed of a braided gold chain and three micro mosaic pendants in a gold rope-twist frame :  a cross with the Greek letters for Iota, Chi, Theta, Upsilon and Sigma and two lozenge shaped pendants representing a peacock and a swallow.

Greek word ichthus is an acrostic for Jesus Christ,  the Son, the Savior : 
Iesous (Jesus), Christos (Christ), Theou (of God), Uiou (the Son), Soter (the Savior)