The Sardines of Ptolemy in the flow of the sea

Shoals of Sardines migrate between different water depths in a daily rhythm. Pisces belong to the 48 constellations of ancient Greek astronomy, as described by Ptolemy. He was a Greek mathematician, geographer, astronomer, astrologer, music theorist and philosopher. In particular, his three works on astronomy, geography and astrology were considered standard scientific works in Europe until the early modern era.