Andres Jojoa
Cleaner wrasses: The cleaner fish of the sea
Under the sea of the tropical Pacific Ocean exists a vibrant and busy city known as the Coral Reef, where an exclusive “spa” is run by remarkable little fish known as cleaner wrasses. These fish, just eight centimeters long, are the guardians of the reef, responsible for maintaining the hygiene and health of their aquatic neighbors. Today’s story centers around one very special cleaner wrasse, named “Clewra,” for short.
Why cleaner wrasses are so important
Cleaner wrasses like Clewra are vital for the health of coral reefs, ecosystems that are currently under threat. Coral reefs are fragile and sensitive to changes in the environment, and climate change has led to widespread coral bleaching. Many reefs across the Indo-Pacific are struggling and cleaner wrasses are part of the solution. They help maintain the balance by keeping the reef fish healthy, which in turn, helps preserve the reef ecosystem.
This is why my research focuses on cleaner wrasses like Clewra. As a student at the University of Hawai’i studying Marine Biology, I wanted to understand how their social behavior and cognitive abilities contribute to the reef’s health, especially in areas still relatively unaffected by coral bleaching. By studying these cleaner wrasses, we can compare their behavior and intelligence across different regions, providing insight into how environmental changes might impact the species in the future.
How cleaner wrasses maintain reef health
With her elegant, shiny purple, blue, and yellow body, Clewra darts around the reef like a little underwater superhero. Her mission is to clean her clients of annoying parasites and dead skin, leaving them refreshed and rejuvenated.
Clewra’s unique talent lies in her ability to perform various gestures to attract and calm her clients. She trembles with excitement to signal she’s ready to clean, her flapping fins creating an irresistible invitation. Some clients even say her touch is like a gentle massage, building trust and bonding. Her “tactile stimulation” helps her clients relax, similar to a relaxing spa experience for humans.
Cleaner wrasses don’t just clean fish for the sake of hygiene, they play a crucial role in the reef’s social structure. Their cleaning services foster a sense of community where fish of all sizes and species line up to get their parasites removed. Even predators like groupers and barracudas show up at the cleaning stations and wait patiently for their turn, demonstrating how cleaner wrasses contribute to peace and cooperation among marine life.
This unique social behavior creates a symbiotic relationship that benefits everyone. Cleaner wrasses are essential because they help prevent diseases by keeping fish free of parasites, ensuring the survival of both the fish and the reef ecosystem. This, in turn, impacts human coastal communities, which rely on healthy reefs for resources and protection from storm surges.
Clewra’s intelligence and skill
What makes Clewra and others of her species truly fascinating is their intelligence. Cleaner wrasses are among the few fish species that can recognize themselves in mirrors, a sign of self-awareness, a rare trait among fish. Clewra, in particular, has a remarkable ability to remember individual clients and their cleaning preferences. Some cleaner wrasses cheat by nibbling at the protective mucus of their clients instead of just eating the parasites, but Clewra is honest and trustworthy. Her clients keep coming back because they know she does her job well.
Researchers have found that the social intelligence of cleaner wrasses may even contribute to the development of their cognitive abilities. Fish that interact with these cleaners must adapt and respond to social cues, making the reef a place of constant learning and communication. My research aims to delve deeper into this intelligence by conducting behavioral and cognitive tests on cleaner wrasses like Clewra.
The ecosystem’s hidden heroes
Cleaner wrasses like Clewra are essential for more than just maintaining cleanliness. Their role in preventing disease and infection ensures the overall health of the reef. Without them, the balance of life on the reef could collapse, causing a ripple effect that would impact both marine life and human coastal communities.