Fish do not serve as a food source for humans only, but for other marine species as well. Other than this, some fish species have important role in the aquatic ecosystem; some contribute directly to the health of other fishes, specially reef fish. In this article, I introduce two important fish species that are tasked with vital fulltime jobs.
Cleaner Wrasse
Cleaning symbiosis is common among fish, where there is a mutual beneficial association between two individuals of two species; one (usually named the cleaner) removes and eats parasites from the surface of the other (usually known as the client). An example of this is the relationship between the cleaner wrasse and other fish, where the wrasse fish gets its food from the parasites on the surface of the other fish while the client gets cleaned.
Wrasses also remove dead and damaged scales and tissues off the surface of other fish, which can be a good medium for some pathogens; this action stimulates mucus production, the first line of fish immune system defense. As such, scientific studies have proved that the cleaner wrasse plays a vital role in the health of fish and coral reefs. Even the diversity and abundance of fish is greater in the places where cleaner wrasses are found.
Most wrasses live in the tropical and subtropical waters of the Atlantic, Indian, and Pacific oceans. Cleaner wrasses set up cleaning stations where they can work for hours cleaning more than 2000 clients of larger fish. One of the wrasse fish species enter sharks’ mouths to eat leftovers the sharks did not swallow. Surprisingly, sharks do not swallow the wrasses while they are cleaning their teeth.
Cleaner fish can be employed in salmon farms to combat sea-lice infestations and for pest control. Moreover, some people tend to transfer cleaner wrasse to huge aquariums to keep them clean. This decreases the population of the fish that depend on them and also affects the variety of reef fish.
Ironically, there is another species of fish that looks like the Blue Streaked Cleaner Wrasse; this is the sabretooth blenny, known as the False Cleaner Wrasse. Fish get confused between the two and approach the sabretooth blenny for cleaning services; when they get close to the false cleaner fish, it bites a chunk off their flesh and runs away.
Parrotfish
Parrotfish are colorful fish that belong to the Scaridae family; they are usually present around the tropical reefs of all the world’s ocean. There are around 80 species of parrotfish, ranging in size between 30 cm and 120 cm; their average life span can reach up to 7 years. The essential task of these species of fish is to clean the reefs, helping the corals stay healthy. The parrotfish has a direct impact on the coral size and density of the coral reef colonies, which also maintain healthy fish that thrive around the coral reefs.
The parrotfish diet depends mainly on the algae growing on the coral reefs; they spend most of their day scraping the hard parts off the coral reefs and eating the algae off of them. Thanks to their strong pointed tipped parrot-like beaks, which can reach the hard-to-reach areas of the coral reefs, and using their strong teeth, the fish can bite the algae inside.
Another species of parrotfish, known as the green humphead, can bite off pieces of the corals, some of which are dead, while eating algae. They have another set of teeth, called pharyngeal teeth, which break these pieces of corals in the fish’s throat. The digested corals turn into sand and the fish excretes it back to the corals and the sea. It is estimated that one large green humphead parrotfish can break up corals enough to create up to 360 kilograms of soft white sand a year. Scientists and researchers discovered that parrotfish contribute to up to 70% of the white sand found on some beaches in Hawaii and the Caribbean.
Just like most marine creatures and fish, parrotfish are facing the danger of overfishing throughout the Caribbean, which is negatively impacting the health of coral reefs. There are many conservation programs dedicated to raise awareness of the importance of protecting the parrotfish.
It is fascinating to discover there are little creatures in the deep sea with fulltime jobs and vital roles that impact the marine ecosystem. Even though they are not paid in return, they certainly receive benefits from their jobs.
References
nationalgeographic.com
nature.org
ncbi.nlm.nih.gov
reefbuilders.com
Cover Image by Freepik