The Algolians are a humanoid species native to the Alpha or Beta Quadrant.
An Algolian attended the biennial Trade Agreements Conference held on Betazed in 2366, and played music in the background. The distinctive song he played was later used as a distress call when Commander Riker, Counselor Troi, and Ambassador Troi were kidnapped by DaiMon Tog. (TNG: "Ménage à Troi")
An Algolian participated in the symposium of the Federation Archaeology Council held aboard the USS Enterprise-D in 2367. (TNG: "Qpid")
- The Algolians' appearance is similar to the Promellians and Pardshay's species and together they likely represent a species type.