 "L. comizo" is endemic to the Iberian Peninsula, where it occurs in both Portugal and Spain.It inhabits the slow-moving middle and lower parts of rivers and reservoirs in the Tagus' and the Guadiana Rivers' drainage basins.Its habitat are deep and almost stagnant waters with abundant aquatic vegetation

Its numbers have declined by about one-third since the 1990s due to unsustainable water usage for agriculture, pollution and competition with introduced species.