marlin sucker
... that the marlin sucker often clings onto its host fish in pairs, with a male under one gill cover and a female under the other?
... that the <b id="mwAzM"><a href="./Marlin_sucker" id="mwAzQ" rel="mw:WikiLink" title="Marlin sucker">marlin sucker</a></b> often clings onto its host fish in pairs, with a male under one <a href="./Operculum_(fish)" id="mwAzU" rel="mw:WikiLink" title="Operculum (fish)">gill cover</a> and a female under the other?