Dominant male <i><a href="//commons.wikimedia.org/wiki/Astatotilapia_burtoni" title="Astatotilapia burtoni">Astatotilapia burtoni</a></i> (Syn. <i><a href="//commons.wikimedia.org/wiki/Haplochromis_burtoni" class="mw-redirect" title="Haplochromis burtoni">Haplochromis burtoni</a></i>) dispute a territorial boundary.
(Image: Russell D. Fernald and Sabrina S. Burmeister)
CC BY 2.5
<i>Social Opportunity Produces Brain Changes in Fish.</i> PLoS Biology Vol. 3/11/2005, e390 <a href="//doi.org/10.1371/journal.pbio.0030390" class="extiw" title="doi:10.1371/journal.pbio.0030390">doi:10.1371/journal.pbio.0030390</a>