Specifically looking into the number of tyrosine hydroxylase (TH)-positive dopaminergic (displaced) amacrine cells, a neuronal subtype suggested to be affected by aging and in neurodegenerative diseases in mammals as well as in fish29,48,49, in the GCL and INL, revealed a similar increase in cell number between 6 weeks and 12 weeks of age, and decrease between 12 weeks and 18 weeks (Fig. 9e; Supplementary Fig. 2). This evidence concerns the gene TH and neurodegenerative disease.