Profits from cryptocurrency is taxed nearly in every country.
(it seems "tax" is in english sometimes used as synonym for fee? otherwise I can't explain why so many people claim "there is no tax only fee for withdrawal/trading". This does not make sense, since real tax has nothing to do with any fees)

@vsyc:
It does not depend on where you are, it does depend on where you live (usually this is where you have your home or where you are more then half a year per year). You pay the taxes to that authority were you also pay all other taxes to.