<a href="https://en.wikipedia.org/wiki/Shoaling_and_schooling" class="extiw" title="en:Shoaling and schooling">Schooling</a> is a behaviour that fish use for socialization, protection and to find a mate. Pictured is <a href="https://en.wikipedia.org/wiki/Black_jack_(fish)" class="extiw" title="en:Black jack (fish)">black jack</a>. f7 1/640 Sony RX100 M2
<a href="//commons.wikimedia.org/wiki/User:Anna_Varona" title="User:Anna Varona">Anna Varona</a>
CC BY 4.0
<span class="int-own-work" lang="en">Own work</span>