Neelix was Reginald Barclay's pet cat. Barclay named the cat after the USS Voyager's Talaxian crewman Neelix. Barclay obtained Neelix after he left the USS Enterprise-E and was attached to the Pathfinder Project.
Neelix was not used to guests. When Deanna Troi visited Barclay in 2376, Neelix helped himself to Troi's chocolate ice cream. Troi suggested that he be introduced to Data's pet cat Spot. (VOY episode: "Pathfinder")
While visiting the Alpha Quadrant in 2376, The Doctor noted that there were several discrepancies in Barclay's otherwise accurate holographic recreation of Voyager, chief among being that the holographic Neelix purred. Deanna attributed this to Neelix the cat. The Doctor told her that Neelix would be honoured by the fact that the cat had been named after him. (VOY episode: "Life Line")