I’ve been spending a lot of time near the cleaning station just off the corner of the Mahukona dock. Two Hawaiian Cleaner Wrasses have occupied this station for many months. All sorts of reef fish come by and pose to be groomed by the little wrasses. It’s a great place to just linger and watch as the fish queue up for cleaning, sometimes chasing each other around, and doing other interesting stuff.
The Hawaiian Cleaner Wrasse is endemic to Hawaii, but three other members of its genus are distributed through the Indo-Pacific. Cleaner wrasses have been getting a lot of press lately. A 2018 National Geographic article describes research showing that Bluestreak Cleaner Wrasses are capable of recognizing their own image in a mirror—the only fish known to be able to do this. https://www.nationalgeographic.com/animals/2018/09/fish-cleaner-wrasse-self-aware-mirror-test-intelligence-news/ Another 2018 article in The Atlantic describes research suggesting that not only do cleaner wrasses benefit the physical health of the fish they service by removing energy-sapping parasites, but they also boost the intelligence of the other fish, again, by removing parasites. https://www.theatlantic.com/science/archive/2018/03/the-fish-that-makes-other-fish-smarter/554924/ If you’re reading this post you should definitely check out both of these fascinating articles.