Tricolia pullus is a species of small sea snail, a marine gastropod mollusk in the family Phasianellidae.

The aperture is roundish oval with a conspicuous operculum is thick and has a white calcareous surface.

The colour pattern of the shiny shell is very variable and goes from cream to white with pink or purple-brown spots spirally distributed in zigzag or flamed patterns.

[2][3] The adults are gonochoristic, i.e. consisting of distinct males and females.

It is found in the sublittoral zone and deeper waters (up to 35 m) in often abundant numbers on red seaweeds (Laurencia, Lomentaria, Mastocarpus), collecting diatoms and detritus.