Depositing EOS based tokens (EOS, ADD, ATD, IQX, MTO) to Bitfinex requires both a deposit address and a deposit memo.
To make a deposit, you need to use both:
On the deposit page, the deposit address is shown at the top, with the deposit memo for each of your wallets shown below. To make a deposit to your Exchange wallet, for example, you will need to use the deposit address shown near the top and the deposit memo next to your Exchange wallet.
A failure to include the deposit memo with your deposit may result in your EOS being lost forever. Please contact support if you have any questions or concerns.