They're in a tank. They literally do not need protection. They also do not care. The hats fill their microbrain compulsions just fine. They don't need your absurd "hey, aren't we all just urchins in hats!?" train of thought.
They're probably living their best lives. They're not being raised for food, they're not living in a wild ocean... they're wearing dapper hats instead of the dead husks of their seaborn brethren.