Laws and regulations with regards to tax varies in each countries. In my country,  Bitcoin currency is not yet rregulated by the government. But i learn from reading that iit is considered as an asset and collection are done once you gain from selling bitcoin.  But if bitcoin demand continue to rise up and prices go up and  the governmenr wod notice that it will be a big addition to their collections,  then definitely our government will create a law to impose a tax from using bitcoin.