Unfamiliar conspecifics increase freezing and shift movement towards immobility in zebrafish, most clearly in males
- 1Uppsala University
Abstract
Familiar companions can buffer stress in zebrafish (Danio rerio), but whether an unfamiliar shoal is itself a stressor, and whether the sexes respond alike, is unclear. We exposed adult zebrafish to a familiar or an unfamiliar shoal for at least 75 min, video-tracked their behaviour over the last 60 min and then measured whole-body cortisol. In males, an unfamiliar shoal increased freezing (+14.5 percentage points), reduced swim bouts and shifted movement towards a frozen state (8% to 49% of frames). In females, the changes were smaller and not significant. With the sexes pooled, whole-body cortisol was 1.6-fold higher after exposure to the unfamiliar shoal. Sex differences were only found for swim bouts and movement states, not for freezing or cortisol. We conclude that an unfamiliar shoal is a likely stressor for zebrafish, with behavioural effects clearest in males. Thus, who a zebrafish shares its tank with is not a neutral background, and the familiarity of conspecifics should be considered whenever fish are placed in new social settings in the lab.
Related
- Spike-wave discharges reflect widespread, but non-uniform, cortical hypersynchrony during immobility
- Horseshoe Bats Recognise the Sex of Conspecifics from Their Echolocation Calls
- Cows visually discriminate and cross-modally recognise familiar and unfamiliar human faces in videos
- Enhanced cortical tracking of unfamiliar languages in both monolinguals and bilinguals
- What drives versus what is required: Sufficient and necessary conditions for consumer intention in an unfamiliar wellness service
BibTeX
@misc{lagman2026unfamiliar,
title = {{Unfamiliar conspecifics increase freezing and shift movement towards immobility in zebrafish, most clearly in males}},
author = {D. Lagman and P. Hubena and S. Winberg and M. Le Greves},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.29.760420},
url = {https://www.biorxiv.org/content/10.64898/2026.10.29.760420v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Unfamiliar conspecifics increase freezing and shift movement towards immobility in zebrafish, most clearly in males
AU - D. Lagman
AU - P. Hubena
AU - S. Winberg
AU - M. Le Greves
PY - 2026
DA - 2026/10/29
PB - bioRxiv
DO - 10.64898/2026.10.29.760420
UR - https://www.biorxiv.org/content/10.64898/2026.10.29.760420v1
AB - Familiar companions can buffer stress in zebrafish (Danio rerio), but whether an unfamiliar shoal is itself a stressor, and whether the sexes respond alike, is unclear. We exposed adult zebrafish to a familiar or an unfamiliar shoal for at least 75 min, video-tracked their behaviour over the last 60 min and then measured whole-body cortisol. In males, an unfamiliar shoal increased freezing (+14.5 percentage points), reduced swim bouts and shifted movement towards a frozen state (8% to 49% of frames). In females, the changes were smaller and not significant. With the sexes pooled, whole-body cortisol was 1.6-fold higher after exposure to the unfamiliar shoal. Sex differences were only found for swim bouts and movement states, not for freezing or cortisol. We conclude that an unfamiliar shoal is a likely stressor for zebrafish, with behavioural effects clearest in males. Thus, who a zebrafish shares its tank with is not a neutral background, and the familiarity of conspecifics should be considered whenever fish are placed in new social settings in the lab.
ER -