The tanaid Zeuxo holdichi is common in intertidal and shallow waters on the French side of the English Channel, with very high abundances along the Calvados coast. The abundances and population dynamics of Z. holdichi were studied during a one-year experiment of benthic colonization of artificial blocks placed upon intertidal oyster culture tables 0.5 m above the seabed. Bi-monthly sampling shows that the colonization was rapid, with abundances reaching 2,000 individuals per m2 in four months. Two peaks were observed at the end of September and the beginning of November, when the abundances exceeded 21,000 individuals per m2. Allometry measurements show that the length of the cephalothorax is a good proxy to estimate the total length of the individuals. The population is mainly composed of male and female adults measuring up to 5.35 mm. Ovigerous females are present from the middle of June to the end of the study, with a high occurrence in August-October. The number of embryos ranges from 5 to 89 for a mean fecundity of 24 embryos per brood pouch. The mean size of the females is 3.5 mm. The mean female/male ratio is 4.28. Considering these traits of life, Z. hodichi possesses high ability to rapidly colonize virgin hard substrates.