Staking crypto rewards is a taxable event and you need to mark the gains for tax purposes. You will have to calculate the Fair Market Value (in USD) when you calculate your taxes each time. All the batches need to be accounted and reported on your tax return as capital gains in accordance with IRS guidelines. If you receive crypto interest from other vehicles, like stocks, bonds, staking or mutual funds, you have to follow the same procedure. To determine the FMV of the interest you received, it should be declared as ordinary income. Tracking the tax implications of cryptos investments can be a complicated process. However, there are plenty of crypto tax software out there that can help you make sense of it all such as CoinTracking, RoboTax, TradeTracker etc.