After stopping new account creation last month due to extreme growth, Bitfinex will now open back up to new users. There are some requirements however. According to Bitfinex:
"However, this extreme growth has not come without challenges. In fact, one month ago we decided to temporarily curtail new account registration in a move designed to preserve the trading, support, and verification experiences of our existing, long-term user base.
New accounts will need to deposit fiat or crypto to achieve minimum account equity of 10,000 USD equivalent before they can trade or offer funding."
Link: https://www.bitfinex.com/posts/registrations-reopen