The myth involving Alrisha refers to one of the myths of the Goddess Aphrodite, who, along with her son Eros, were immersed into the Euphrates River when they were trying to escape from the Monster Typhon and from where they were saved by two fish. It is said that later on, in gratitude, the Goddess immortalized their “saviors” giving them a place on the starry heavens.
"Those stars in Pisces which are in the head of the southern fish have the same influence as Mercury, and, in some degree, as Saturn: those in the body are like Jupiter and Mercury: those in the tail and in the southern line are like Saturn, and, moderately, like Mercury. In the northern fish, those on its body and backbone resemble Jupiter, and also Venus in some degree: those in the northern line are like Saturn and Jupiter." By the Cabalists, Pisces is associated with the Hebrew letter Pé and the 17th Tarot Trump "The Stars." [Robson (2), p.57.]
(1) Symbols in primitive Christianity http://en.wikibooks.org/wiki/Biblical_Studies/Christianity/Christian_art/Primitive
(2) Fixed Stars and Constellations in Astrology, Vivian E. Robson, 1923].