Representative activity (A), waking activity (B) and sleep (C) traces of vehicle (blue) and bopindolol (red) treated zebrafish larvae. Bar graphs of activity (D), waking activity (E), sleep (F), sleep bout number (G), sleep bout length (H) and sleep latency (I) from two combined experiments (n > 140 for each condition). Bars represent mean ± s.e.m. n indicates number of larvae. *, p < 0.05; **, p < 0.001; ***, p < 0.0001 by one-way ANOVA.