The constellation resembles two roundish objects, each of which is tied to the same point by a long length of string . Generally the objects have been considered as fish, although since by including fainter stars visible to the naked eye, the strings themself take on the appearance of stick-figure bodies (with the roundish objects thus becoming heads). Some forms of early Greek mythology viewed it as men bound to a point. It is generally thought that in earlier depictions, only the constellation Piscis Austrinus was considered to be a fish.

According to one version in Greek mythology, this constellation represents fish into which Aphrodite and her son Eros transformed in order to escape the monstrous Typhon. The two fishes are often depicted tied together with a cord (or their tails), to make sure they do not lose one another.

According to another version, since the binding point is below the ecliptic, and thus considered to represent being in the underworld, and that one of the figures (the one on the left) appears to escape, but the other (on the right) seems to head back toward the ecliptic, then, together with Cetus (another constellation in the Zodiac sign of Pisces), this may have formed the basis of the myth of the capture of Cerberus, one of The Twelve Labours of Herakles