Police say the fracas happened between 02:30 and 03:00 on Sunday 19 July.
Guernsey Police is asking for witnesses or anyone else with information to come forward.
People who saw or heard anything can contact PC 56 Gillam or PC 116 Ormrod on 725111 or call Crimestoppers anonymously on 0800 555 111.
Pictured top: The fight happened around by the Quay and the Town Church, police said.