The incident happened shortly before 8.30pm on Friday at the Hare and Hounds in Toller Lane.
West Yorkshire Police said a large group of people were fighting in the pool room, but no weapons were used during the incident.
Several people were injured and one man sustained a serious head injury, which needed a number of stitches.
Now investigators are urging anyone who saw the incident and can help with their enquiry to come forward.
Contact police on 101 or use the live chat facility on the force website, quoting crime reference 13180626799.
Alternatively, call the independent charity Crimestoppers anonymously on 0800 555 111.