BRIEF COMMUNICATION Response to underwater laser pointer in the Orange-finned Anemonefish Amphiprion chrysopterus and three-spot damselfish Dascyllus trimaculatus Emilie Cohn | Patrick Cole | Amanda Haymaker | Austin M. Garner | Richard L. Londraville University of Akron, Program in Integrated Bioscience, Department of Biology, Akron, Ohio, USA Correspondence Richard L. Londraville, University of Akron, Department of Biology, Akron, OH, 44325-3908, USA, Email: londraville@uakron.edu Abstract Response of orange-finned anemonefish Amphiprion chrysopterus and three-spot damselfish Dascyllus trimaculatus to red laser-pointer light was studied in Mo'orea, French Polynesia. Four magnificent anemones Heteractis magnifica and their resident fish were observed for typical behaviours (biting, chasing, hiding, posing, lunging and retreating) with and without exposure to laser-pointer light. Lunging behaviour increased significantly for both fish species upon exposure to laser-pointer light; none of the other behaviours changed significantly. We advance the hypothesis that orange-finned anemonefish and three-spot damselfish interpret laser pointer stimula- tion as a territorial threat. KEYWORDS anemonefish, boldness, French Polynesia, laser pointer, Moorea Underwater laser pointers are popular scuba diving accessories, as they precisely and easily indicate features of interest to dive partners (e.g., can be used to point out animals in refugia to dive partners). As a consequence of their use, divers documented that reef fish respond to the spot of laser light with chasing and biting (YouTube, 2015). In order to study this behaviour, we observed orange-finned anemonefish Amphiprion chrysopterus (Cuvier 1830) and three-spot damselfish Dascyllus trimaculatus (Rüppell 1829) resident on magnifi- cent anemones Heteractus magnifica in Mo'orea, French Polynesia. Anemonefish offer several advantages to characterise novel behaviour in that the same individual fish can be observed repeatedly on easily recognised sessile anemones (Fautin, 1991), they have well- established behavioural repertoires (Chen & Hsieh, 2017; Mills et al., 2018; Nanninga et al., 2017), and they respond to laser-pointer light (this study). Using fish resident on anemones, we tested the hypothe- sis that A. chrysopterus and D. trimaculatus perceive the artificial stim- ulus of laser-pointer light as a territorial threat. A cluster of 4 H.magnifica, within a 2 × 6 m area at 1–2 m depth, were observed while snorkelling in Oponoho Bay, Mo'orea French Polynesia (17  29 0 43.7 00 S, 149  51 0 06.8 00 W) 16–28 May 2019. Each anemone was c. 40 cm in diameter and had a single resident adult anemonefish with 2–4 resident three-spot damselfish (juveniles and adults) except for anemone #2 with only damselfish. Anemones and resident fish were chosen after consultation with local researchers, so as not to be included in several long-term anemonefish studies on the island (Mills et al., 2018; Nanninga et al., 2017; Norin et al., 2018). Thus, these sites and these resident fish should have less history with researchers than other individuals on Mo'orea (although we cannot account for tourist interactions). Water temperature during the obser- vations was 28–30  C and although some other anemones in the bay were bleached, anemones in this study were not. All observations were conducted soon after sunrise (06:30–08:30 h) and at dusk (16:00–17:30 h) to maximise laser contrast. All observations were made by two observers while snorkelling, with a third snorkeler manipulating the laser pointer. Snorkelers swam to 3 m from the anemones, waited 6 min for the fish to acclimate to their presence (Nanninga et al., 2017), then recorded numbers of behaviours per fish (averaged for 2 observers per fish) for 2.5 min. Immediately after observation without laser pointer stimulation, a red-light laser pointer (Trident DL70; www.scuba.com) was aimed at Received: 12 August 2019 Accepted: 4 November 2019 DOI: 10.1111/jfb.14192 FISH 274 © 2019 The Fisheries Society of the British Isles J Fish Biol. 2020;96:274–277. wileyonlinelibrary.com/journal/jfb