Dolphin
Respected and loved today, this intelligent marine mammal had a venerable treatment
in the Hellenic antiquity as well - as reflected in artifacts, mythology, and finally - coinage. 
In some sense, Aesop's well-known fable where the duplicitious monkey is juxtaposed
to the honest, yet not gullible dolphin, summarizes ancient views of this noble sea animal.
Tales of dophins' rescues of humans in distress abound, and some of them - like that
of the poet-singer Arion, and particularly the one of Taras, the founder of
Tarentum in Sicily - have found
artistically impressive expression on coinage. Other times, dolphins appear in less
obvious contexts (like the impressive "eagle attacking doplhin" composition of two Black
Sea cities), as attributes of Poseidon, or
perhaps just as an apparent symbol of grace in the marine world.