The zebrafish has been gaining prominence in the field of behavioural brain research as this species offers a good balance between system complexity and practical simplicity. While the number of studies examining the behaviour of zebrafish has exponentially increased over the past decade, the need is still substantial for paradigms capable of assessing cognitive and mnemonic characteristics of this species. Here we describe and utilize a novel visual discrimination task with which we evaluated acquisition of CS (colour)-US (sight of conspecifics) association in adult zebrafish. We report significant acquisition of CS-US association indicated by the increased time the fish spent in and the increased frequency of visits of the target chamber during a probe trial in the absence of reward. Given the simplicity of the apparatus and procedure, we conclude that the new task may be employed to assay learning and memory in adult zebrafish in an efficient manner.