Peek-A-Boo test: a simple test for assessing the effect of diazepam on medaka (Oryzias latipes) behavior
Abstract: The potential of pharmaceuticals and personal care products to alter the behavior of aquatic organisms is a growing concern. To assess the actual effect of PPCPs on aquatic organisms, the method of a simple but effective behavior test has been required. In this study, we devised a simple behavior test (Peek-A-Boo test) to assess the effect of anxiolytics on model fish behavior (medaka, Oryzias latipes). In the Peek-A-Boo test, we investigated the response of medaka to the picture of a predator fish (donko fish, Odontobutis obscura). The diazepam exposure test (0.8, 4, 20, 100 µg/L) revealed that the time taken for test medaka to approach the picture was 0.22–0.65 fold shortened and the time spent by test medaka in the close area to the picture was 1.8–2.7 fold elongated in all of the diazepam exposure groups compared with the solvent control group (P < 0.05). Hence, it was confirmed that the Peek-A-Boo test could detect the medaka behavioral alteration caused by diazepam with high sensitivity. The Peek-A-Boo test devised in this study is a simple behavior test with high sensitivity for fish behavioral alteration. Files: coord_images.zip includes the csv files of fish swimming coordinates in the experiment using five other fish images. coord_diazepam.zip includes the csv files of fish swimming coordinates in the diazepam exposure experiment.