Currently BlockFi does not offer an API to enable automatic imports. If you would like to request this feature from BlockFi, please click to tweet this message!
Login to your BlockFi account.
Click on the Reports option under the user profile dropdown menu.
Scroll to the very bottom of the page to All Transactions and click on Download All to get your full transaction history downloaded to a CSV file.
Navigate to the BlockFi tab on CryptoTrader.Tax and drag the file you just downloaded into the blue box.