There are two types of taxes you need to worry about with Bitcoin.
The first is regular income tax. If you earn bitcoins by mining or doing any other kind of work, you must declare the market value of your bitcoins as earned income whether you sell them or not.
So you are telling that if i draw a great painting, i must decrale its market value as earned income, whether i sell it or not?
No, because that painting isn't payment for services rendered, which is what mined bitcoins are. They are the payment that miners receive for securing the Bitcoin network. If you receive
anything as a
payment for services or any other kind of work you did, that's income and you have to declare it.
Bitcoins are a token like a stock. Until the token is sold there is no tax levied. They do fall under capital gains taxes.
For example if your employer pays you in stocks as well as salary, only your income is declared under regular income taxes. Until you sell the stock there are no taxes generated since they fall under capital gains. Bitcoins are no different.