if what you keep is for example the mined, we could say that it is, but it happens that everything depends on where the story begins, if we start from the fact that you already have the cryptocurrency, it is true, you are not taxable until your conversion to FIAT, but if we start the story since you have the FIAT money to acquire the cryptocurrency, and that money will be subject to taxes as part of your income when you invest or spend it.

Now, the declaration of investment falls into a duality, because it is an investment in shares or speculative, in any case the recognition or not of the governments of the figure, it is after you declare the FIAT money in your account and you must pay for that income obtained.

For all the above, it is not worth mentioning tax frauds, or tax returns not presented, and those are particular cases subject to persecution and particular analysis. It is as if we talk about someone who receives regular income and decides not to declare taxes, is it possible? Yes, but that is punishable by law, and this will take care of the situation.