Fig. 1

Schematic representation of the experimental protocol at 5 days post-fertilization (dpf), 21 dpf, and 6-months old adult fish. Experiments done at the three ages are separated and denoted with purple outline. Blue arrows show timeline of procedures while orange dotted lines represent virtual division of testing arenas into relevant areas. For 5 dpf larval fish (a), general locomotion was observed during a baseline period, followed by PTZ-induced hyperlocomotion. Representative examples of behavioural traces are provided to illustrate typical locomotion (wells A1 and B2), immobility (well B1), and hyperlocomotion (well A2). For 21 dpf fish (b), three traces illustrate preference (top), indifference (middle), and aversion (bottom) to social stimuli. The dotted orange lines mark the social and non-social zone used for calculation of social preference index [SPI]. For adult fish, the dotted orange lines indicate the line between border and center during (c) baseline open field testing, five zones during social preference testing (d) with zone 1 being closest to the shoal [social zone] and zone 5 being the furthest away from the shoal during social behavioural testing, and the division of water column into vertical top, middle and bottom areas (e) during novel tank diving test. Representative traces below show bottom-dwelling vs. exploration in higher water column in the open-field, no preference vs. social preference during the social behaviour test, and exploration of bottom only, middle, and top areas of the novel tank. After the behavioural testing, all fish were (f) fin-clipped under anaesthesia for genotyping. Separate group of experimentally naïve adult fish were used to measure whole-body cortisol levels (g) using enzyme immunoassay