Eros was the mischievous god of love, a minion and constant companion of the goddess Aphrodite. But why the dolphin or fish? A quick Internet search brings up the answer.
Typhon, a Greek god, was bad and treated as an outcast by other gods. One day Typhon appeared and threatened the other gods. They all knew what Typhon was capable of, so each and every god made a run for it. In order to escape him, most of the gods turned themselves into animals, as to gain speed and agility. The only ones not to were Aphrodite and Eros, the gods of love. With Typhon closing in on them they were in trouble. At the last moment, two fish appear and they let Aphrodite and Eros jump on their backs. This way, the two managed to avoid getting caught by the evil Typhon.
Pseudo-Hyginus,
Astronomica 2. 30 (trans. Grant) (Roman mythographer C2nd A.D.) :
“Fishes. Diognetus Erythraeus says that once Venus
[Aphrodite] and her son Cupid [Eros] came in Syria to the river Euphrates.
There Typhon [Typhoeus], of whom we have already spoken, suddenly appeared.
Venus [Aphrodite] and her son threw themselves into the river and there changed
their forms to fishes, and by so doing this escaped danger. So afterwards the
Syrians, who are adjacent to these regions, stopped eating fish, fearing to
catch them lest with like reason they seem either to oppose the protection of
the gods, or to entrap the gods themselves.”
Ovid, Fasti 2. 458 ff (trans. Boyle) (Roman poetry C1st B.C. to C1st A.D.) :
“Pisces, heaven’s horses. They say that you and your brother
(for your stars gleam together) ferried two gods on your backs. Once Dione
[Venus-Aphrodite], in flight from terrible Typhon [Typhoeus] (when Jupiter
[Zeus] armed in heaven’s defence), reached the Euphrates with tiny Cupidos
(Cupid) [Eros] in tow and sat by the hem of Palestine’s stream. Poplars and
reeds dominated the tops of the banks; willows, too, offered hope of
concealment. While she hid, the wood roared with wind. She pales with fear, and
believes a hostile band approaches. As she clutched son to breast, she cries :
‘To the rescue, Nymphae (Nymphs), and bring help to two divinities.’ No delay;
she leapt. Twin fish went underneath them; for which, you see, the present
stars are named. Hence timid Syrians think it wrong to serve up this species;
they defile no mouths with fish.’”
