Sources : Flying Fish

Pliny the Elder [1st century CE] (Natural History, Book 9, 34): Arcadia also has a marvel in its exocoetus, so called because it climbs out on to the land to sleep. In the district of the river Clitorius this fish is said to have a voice and no gills; the same variety is by some people called the Adonis fish. - [Rackham translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Fish 7.36): Ezochius is a fish in Arcadia, as Pliny says. It goes out onto the dry land to sleep, and cannot live without sleep. With these fishes may be signified those who, fleeing the worldly sea, scorn its abundance of delights, and in the aridity of poverty, as in the desert with Helia, fleeing the luxury of Jezebel and the tumult of the vanity of the world, rest as if in a dream in the privacy of contemplation. - [Badke translation/paraphrase]