A study was carried out along three years, on distribution and possible competence between the two thiarid species present in Lake Hanabanilla, Cuba: Melanoides tuberculata and Tarebia granifera. Both species presented significant differences as to its abundance within a determined microhabitat, but they could match their densities for the total sampled area. These variations were mainly due to the ratio of juveniles in each species. Interaction was only detected when high abundance values were reached and some limitation resource existed (mainly in the nearest area to the shore). Both thiarids presented a high nest width, but Tarebia granifera was slightly higher; besides, this species was dominant at the end of the study at most of the sampled areas.