Experimental design. Zebrafish dyads were established on Day 1, had welfare endpoints checked during Days 2–4, after which hierarchy formation was verified on Day 5. After behavioral observations of aggressive and territorial behavior, animals were transferred and observed individually in the novel tank test. See the “Methods” section for more information.

Swarmplots and Cumming estimation plots for variables in the novel tank test. (A) Time spent at the bottom third of the tank. (B) Time spent at the top third of the tank. (C) Absolute turn angle. (D) Freezing duration. (E) Swimming speed. The mean difference for three comparisons against the shared control (male controls) in the above Cumming estimation plots. The raw data is plotted on the upper axes. On the lower axes, mean differences are plotted as bootstrap sampling distributions. Each mean difference is depicted as a dot. Each 95% confidence interval is indicated by the ends of the vertical error bars. 5,000 bootstrap samples were taken; the confidence interval is bias-corrected and accelerated.