This confocal image depicts neurodegeneration in the retina of an aged zebrafish with a mutation in the c9orf72 gene. Natalia Jaroszynska and colleagues explored the consequences of this mutation in vivo because it is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia. Cell nuclei (blue) and rod (green) and cone photoreceptors (magenta) are labelled by immunofluorescence. This technique revealed that mutant zebrafish have a reduction of both photoreceptor types and a mislocalization of rhodopsin to the outer layer of the retina. See the article by Jaroszynska et al. for more information on what they observed in c9orf72-deficient zebrafish. Cover image: Natalia Jaroszynska.