In many jurisdictions, staking rewards are treated as ordinary income at the fair market value of the tokens on the date you gain control of them, separate from any capital gain or loss you realize later when you eventually sell those tokens. That means a tax liability can arise even if you never converted the rewards to fiat currency.
Rules vary significantly by country, and some jurisdictions are still actively developing guidance specific to staking as opposed to other forms of crypto income. Some tax authorities have also considered alternative treatments — such as taxing rewards only upon sale — for certain staking structures, so the general 'income on receipt' pattern is common but not universal.
This is general information, not tax advice. Staking tax treatment depends on your specific jurisdiction, the mechanics of the staking method you use (direct delegation, exchange staking, liquid staking), and rules that continue to evolve. Consult a qualified tax professional familiar with digital assets in your jurisdiction before filing.