It's even incredibly rare for humans - we're currently in an age of plenty and abundance, with more people living better lives than at any other point in the history of our species.
Overfishing and the geopolitical nature of enforcement and exploitation aren't something we can affect at an individual level, but these aquarium staff are doing a good thing, making a pretty good life for a sunfish. An actual companion would be better, but as long as the cutouts are triggering relief for whatever social needs being affected, that's a good deal for the sunfish.