Micturition in Zebrafish. Pericardial injections were performed in adult fish as described. Counter injection into the cloacal channel was performed with dextran-conjugated Alexa 568. Separate channels were obtained by alternating prisms. Within 10 minutes, urine was expelled from the dorsal urethral meatus. Excreted urine was regularly washed away using a pipette in order to continually visualize the micturition process. Timescale is approximately 16x acquired speed. Images have same size scale as images in Figure 9d-f.