Bitcoin's price is still a puzzle despite the highly evolving literature. This paper tries to identify some variables that explain its evolution. We show that macroeconomic variables and Google searches tend not to explain bitcoin's price anymore. We are therefore interested in variables specific to the crypto-assets ecosystem: volumes of ether, ripple and tether. The negative relationship that emerges from the results shows that these crypto-assets are used for price manipulation or pump and dump activities on the bitcoin market.