Adult neurogenesis has been subject to increasing interest over the past decades. In fish, this ability to create new neurons is impressive compared to most other vertebrate taxa. Several factors are known to influence adult neurogenesis, like environmental enrichment, learning, exercise, stress and aging. In this study, zebrafish were isolated and exposed to two different environments, a barren environment (control group) and an enriched environment (enriched group). The enriched environment was aquaria supplied with gravel and plastic plants, while the barren aquaria were left empty. Neurogenesis in the zebrafish was determined by proliferating cell nuclear antigen (PCNA) – immunohistochemistry. After development of a suitable protocol, this method gave staining of a quality that allowed quantification of stained nuclei in the telencephalic tissue. Number of PCNA positive cells per telencephalic volume, response time to distributed food, locomotion activity, cortisol levels and growth rate were measured and compared between the groups. Environmental enrichment led to a strong tendency towards higher neurogenesis, which is in concert with several studies performed of mammals. Also, a significantly higher inter-individual variation in number of new telencephalic cells was observed in the enriched group, indicating that heterogenic environments leads to greater heterogeneity in neurogenesis within a population. Response time to the distributed food was not significantly different between the groups, although the enriched group tended to have longer response time. The control group had significantly higher locomotor activity than the enriched group. In both experimental groups, the effect of time was significant and led to a decrease in both response time and locomotor activity. Whole-body cortisol levels were significantly higher in the enriched group, although this was likely an effect of longer capture time in this environment. This is the first study to examine environmental enrichment and its effects on neurogenesis and behaviour in zebrafish.