The poet ends his poem with, "Notice Neptune, though,/ Taming a sea-horse, thought a rarity". What is this referring to?

The ending lines of the poem refer to the Roman god Neptune, who is known as the god of the sea. The "sea-horse" in this context could be a literal sea creature, or it could metaphorically represent something that is difficult to control or tame, such as the sea itself or even one's own emotions or Knowee AI is a powerful AI-powered study tool designed to help you to solve study problem.