Protein aggregation is a hallmark of many age-related pathologies and, in particular, of neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. The teleost Nothobranchius furzeri shows the shortest median life span among all vertebrate animal models and has recently gained popularity as a convenient model for experimental approaches to aging. Immunofluorescence staining is the primary technique used to visualize the distribution of proteins in fixed cells and tissues and it has proven to be a powerful tool to study aggregates and proteins involved in neurodegenerative diseases. Specifically, immunofluorescence staining allows for precise localization of aggregates in specific cell types and can be used to identify the proteins constituting such aggregates. To facilitate the study of aggregate-related pathologies in the context of aging using the new model N. furzeri , we report a protocol to visualize general protein aggregates and specific proteins optimized for N. furzeri brain cryosections.