Brown Trout (<i>Salmo trutta fario</i>) illustration from USFWS. I replaced grey/blue background with white BG. I release the background modification into the public domain.
U.S. Fish and Wildlife Service
Unknown date<div style="display: none;">Unknown date</div>
<a rel="nofollow" class="external text" href="https://www8.nos.noaa.gov/coris_glossary/index.aspx?letter=e">small version</a>, modified version: <a rel="nofollow" class="external autonumber" href="https://www.fws.gov/mountain-prairie/fish/fish.html">[1]</a>, <a rel="nofollow" class="external autonumber" href="https://www.fws.gov/mountain-prairie/fish/fish5.jpg">[2]</a>