Lord Krishna is human avatar of lord Vishnu, he came to earth to equate the balance of goodness and evil.
In Bhagwat Gita, Lord Krishna states "whenever the balance of the universe is distributed by external interference from any of its parts, then I reveal myself as the power of external balancing. For the protection of those who are in harmony, and the rectification of everything disharmonious, I incarnate Myself at every juncture of time. " This idol of Lord Krishna is made of brass and silver coated with antique finish in blue tone. The blue tone of the idol symbolizes the depth and calmness of the ocean.