The Olbians really liked dolphins, and minted many types of coins with them on it.
There are the famous “dolphin coins” themselves:
A more detailed example of which you can see here:
As well as more normal coins, such as this one which has a Gorgoneion on the obverse:
You’ll note that the dolphin is being carried off by an eagle. This is a common motif, and I’m not sure if it refers to some myth I’m not familiar with or an everyday occurrence. In which case, fuck, they must have big eagles in the Ukraine.
On this coin (with a kneeling Herakles on the obverse) we find a wheel with dolphins in the cardinal directions, for reasons.
Dolphins also appear in conjunction with some kind of flower and an eight-rayed star, as well as by themselves.
I wonder if these are the dolphins of Dionysos or of Apollon. I’ve seen good arguments either way, as well as scholars put forth that they have some association with Poseidon. While certainly possible, the other two are much more prominent members of the Olbian pantheon so I think it unlikely.