SB 10.16.6
tam canda-vega-visa-viryam aveksya tena
dustam nadim ca khala-samyamanavatarah
krsnah kadambam adhiruhya tato ’ti-tungam
asphotya gadha-rasano nyapatad visode
Translation:
Lord Krsna saw how the Kaliya serpent had polluted the Yamuna River with his terribly powerful poison. Since Krsna had descended from the spiritual world specifically to subdue envious demons, the Lord immediately climbed to the top of a very high kadamba tree and prepared Himself for battle. He tightened His belt, slapped His arms and then jumped into the poisonous water.
Purport:
According to the acaryas, Lord Krsna also tied back the locks of His hair as He prepared to do battle with Kaliya.