Peacock feather contains all the 7 colours in it. entire universe is covered by akasha(ether) appears blue in day times and black in night.Krishna is identified by 'Blue' & 'Black'. Krishna paksha in Indian calender i.e, the darker phase of 14 days of the moon. the entire range of colours (we mortal beings) is in him. In virtue he is colourless but in the day he appears blue, black in the night to our vision and in between make us discuss all this multi-coloured multi-perceptional views.
Draupadi prays to Krishna: "Krishna!" she cried. "O Govinda! O Keshava! O beloved of the gopis and Lord of Vrindavana! O Janardana, You are the destroyer of all affliction. I am sinking into the Kaurava ocean. O Lord, O soul of the universe, O creator of the world, save me! I am distressed and losing my senses in this evil assembly!"~Mahabharata