The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.Īnimals that repeatedly encounter each other in communities structured by dominance hierarchies or territoriality often develop social signals facilitating the recognition of individuals. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.ĭata Availability: Data are available in the and paper and its Supporting Information files.įunding: This work was supported by awards to Masanori Kohda, , and. Received: FebruAccepted: ApPublished: May 18, 2016Ĭopyright: © 2016 Satoh et al. PLoS ONE 11(5):Įditor: Daniel Osorio, University of Sussex, UNITED KINGDOM We discuss the significance of facial coloration for individual recognition in fish compared with birds and mammals.Ĭitation: Satoh S, Tanaka H, Kohda M (2016) Facial Recognition in a Discus Fish (Cichlidae): Experimental Approach Using Digital Models. We conclude that to identify individuals this fish does not depend on frontal color patterns but does on lateral facial color patterns, although they have unique color patterns on the other parts of body. Focal fish frequently performed partner-specific displays towards partner-face models, and did aggressive displays towards models of non-partner’s faces. Digital models of four different combinations of familiar and unfamiliar fish faces and bodies were displayed in frontal and lateral views. We used modified digital models to examine whether discus fish use only facial coloration for individual recognition.

If the facial area is an inherently important site for the visual cues, this species will use facial patterns for individual recognition, but otherwise they will use patterns on other body parts as well. Discus fish have individual-specific coloration patterns on entire body including the facial area, frontal head, trunk and vertical fins.

However, it remains to be determined whether the facial area is an especially favorable site for visual signals in fish, and if so why? The monogamous discus fish, Symphysopdon aequifasciatus (Cichlidae), is capable of visually distinguishing its pair-partner from other conspecifics. For example, a cichlid fish and a damselfish will use individual-specific color patterns that develop only in the facial area. Many fish also visually recognize other conspecifics individually, and previous studies report that facial color patterns can be an initial signal for individual recognition. A number of mammals and birds are known to be capable of visually discriminating between familiar and unfamiliar individuals, depending on facial patterns in some species.

Discus cichlid