Can you find a better picture of the window on the opposite side from this pic?
my best guess.
Looks Greek to me.
Carrying a Tident.
Guessing it probably has a fish tail as it looks like it is coming from the ocean or water.
Triton or the Tritones?
They were mermaid like deities.
Also, could be this.
Saw this while reading up on Tritons.
Ichthyocentaurs
https://en.wikipedia.org/wiki/Ichthyocentaurs