Btc fluctuates because of the huge interest of the people knowing that bitcoin is a good source of being wealthy as early adopters experiencing now they are all millionaires.Most people nowadays tend to take risk in investing through bitcoin because they believe that bitcoin is very capable of making high profit.So as popularity grow more and be known in the world increase of demand in the market also increases while there were less supplies that make its price fluctuating.If bitcoin would be widely known to the entire world possibilities would be price will reach to the highest peak.