**1. Introduction**

Epibiotic is a type of association in which an organism lives on the surface layer of another organism called basibiont, these nonparasitic organisms are known as epibionts [1, 2]. The shells of gastropod and bivalve mollusks represent a suitable habitat for the settlement of various species of algae, viruses or fungi [3–6]. Different studies have focused on epiphytic diatoms of grasses and marine macroalgae [7–9]; in copepods of the species *Farranula gibbula*, the epibiotic diatom *Pseudohimantidium pacificum* has been observed [10]. Very little information exists on symbiotic associations between algae and crustaceans or marine planktonic mollusks, being able to cite what was observed in *Peringia ulvae* (formerly *Hydrobia ulvae*) and diatoms *Cocconeis placentula* and *Achnanthes lemmermannii*, also cyanophytes and bacteria in its Shell [5]. Based on the above, the objective of this work was to identify epizoic species present in the shells of the larval stages of the marine gastropod mollusk, *Aliger gigas*.
