Pisces, the "Fish" (plural), is a constellation, one of the twelve Signs of the Zodiac. It is the twelfth astrological sign, and comes between Aquarius the Water-Bearer and Aries the Ram. As a sun sign, it represents the dates of February 20 through March 20, and the last month of the ancient pagan calendar at the end of the year, just before Spring.
An early influence on the growth of the New Age movement was the founding of the Theosophical Society by Madame Blavatsky in 1875, but it gained most popularity in the 1960s, when its followers looked forward to the dawning of the Age of Aquarius and the passing of the Age of Pisces which they saw as dominated by Christianity. The Age of Pisces, signified by the astrological Zodiac sign of two fish swimming in opposite directions, is seen by New Agers as evident in the early Christian use of the acronym ΙΧΘΥΣ IChThUS, Greek for "fish" ιχθύς ichthys (origin of the word for the scientific study of fish Ichthyology), as representing Ίησούς Χριστός Θεός Ύίός Σωτέρ – Ίησούς (Iesous), Χριστός (Christos), Θεός (Theos), Ύίός (hUios), Σωτέρ (Soter) – "Jesus Christ God's Son Savior".