Mixed-species groups are common in nature and confers many benefits to group members. However, individuals can experience these features of group-living differently due to both within- and between-species differences in behavior. Consistent individual differences in behavior may have important consequences on the transmission of relevant social information within a group. In fact, access to conspecific and heterospecific social information may be a major behavioral driver in the formation and maintenance of mixed-species groups. In this study, we develop a null model of collective decision-making for a single-species group. We assess how likely the group is to select ‘moving’ to a correct option under various conditions involving environmental uncertainty and the confidence placed on socially derived information. We plan to extend on this model by adding another species which differs in social reliance behaviors to explore the conditions under which mixed-species groups are expected to form. In a current empirical study, I test model assumptions by assaying for behavioral variation in the clonal Amazon (Poecilia formosa) and Atlantic molly (Poecilia mexicana) which exist in mixed-species groups.