The attack took place at 2.40am on Saturday in Commercial Road.
The victim, a 24-year-old man, was with two friends by the fountains when he was approached by four men who beat him.
The attackers left in the direction of Cornwallis Avenue, with two women they were with.
The victim suffered head injuries, a broken nose and numerous fractures around his eye.
One of the men police want to speak to is described as: white, 5ft 8ins, with dark long-ish hair. He was wearing boxer shorts, a dark coloured t-shirt and socks. He was wet as he had just been swimming in the fountain.
Another of the men is described as: white, 6ft, of stocky build and wearing a white t-shirt.
Those with details about the attack should call police on 101 quoting 44220200584.