Do fish get dirty? Seems like a dumb question, right? After all, fish live in a giant bathtub.
Turns out at night while fish are sleeping or maybe at other times when they are just chilling or hanging, they pick up tiny parasites, known as extoparasites, which attach themselves on a fish’s body. These parasites along with bacteria, algae and dead skin need to be removed from the fish’s skin, mouth and gills to keep the fish from getting sick.
Parasitic infestations can kill fish, or impair a fish’s ability to swim, hunt or mate. Without removal, parasites and algae can clog gills suffocating a fish, or cause dangerous infections.
I’m cruising along the reef and there, under a ledge, I see it — a stoplight parrot fish being cleaned by what I think is a cleaner fish. A song released in 1974, written and recorded by Jim Croce, plays in my mind: “So baby, don't expect to see me with no double martini in any high-brow society news cause I got them steadily depressin', low down mind messin, workin at the car wash blues.”
When you get dirty, as my wife likes to say, you “jump” in the shower. (Jumping in the shower seems dangerous, but who am I to say being older and all?)
When fish need to be cleaned, they pull into the nearest cleaning station, a place on the reef where special fish or shrimp known as cleaners set up business.
Watching fish being cleaned at a cleaning station reminds me of a busy carwash. A fish pulls in and positions itself by signaling that its wants to be cleaned by flaring its gills or settling down with its mouth wide open. Then, one or more cleaners go to work. The sparkling clean fish leaves and another fish pulls forward
The “works” can even involve a mouth and tooth cleanup.
Who are these cleaner fish? Most are cleaner wrasse, gobies, or cleaner shrimp.
In exchange for their services the cleaners get a steady supply of food and nutrients and receive a strange immunity, such as those that clean inside the mouths of sharks, from predators,.
Cleaning stations are often located on top of coral heads, underneath ledges or in between outcroppings.
Cleaner fish and shrimp even clean scuba divers. Sometimes when a diver swims near a cleaning station, the cleaners may pick dead skin cells off the diver’s hands and face or, if the diver takes out her regulator and opens her mouth, the cleaner fish or shrimp may become a gentle dental hygienist. (In the interest of political correctness, I need to mention that the cleaners will clean both male and female divers.)
Cleaning stations are one of the more interesting places to visit when diving on a reef. Divers who try to cover a large area by swimming too fast may miss the action. Watching a fish being cleaned or being cleaned yourself is a memorable experience.
A large variety of fish visit cleaning stations. Biologists use cleaning stations to study the demographics of fish and to identify signs of disease and disability in fish populations.
Cleaner fish and shrimp have colors and designs to identify themselves to other fish and to keep the cleaner fish safe. Just to be certain, on the safe part, cleaners use bodily contact and caress with their fins to calm the fish being cleaned.
Cleaner fish usually are blue and yellow with striped body patterns including dark stripes along each side.
OK, having said all that, I got fooled. Turns out it happens to fish too.
To avoid the comments of some sharp eyed reader, I sent a copy of my parrot fish image to Mary Tagliareni, deputy superintendent for operations and education, Florida Keys National Marine Sanctuary, to verify the cleaner wrasse. She, in turn, sent it to Billy D. Causey, Ph.D., the southeast regional director of the National Oceanic and Atmospheric Administration (NOAA) Office of National Marine Sanctuaries.
He sent back an e-mail saying: “It looks very much like a wrasse blenny. They don't really clean fish, but instead mimic cleaners. They hide in burrows and come out and actually bite the host fish. They look a lot like juvenile bluehead wrasse.”
The wrasse blenny is a good mimic both in coloration and behavior by copying the unusual “dance” of the cleaner wrasse by spreading its caudal (tail) fin and oscillating its posterior (rear) end up and down
Besides biting the unsuspecting client fish, and sometimes succeeding at tearing away portions of fin, the wrasse blenny preys on small fish and shrimp. Most wrasse blenny attacks occur on juvenile fish because older fish, unlike me, learn to distinguish between real and fake cleaner fish and avoid being fooled.
“But no matter how smooth I talked; they wouldn't listen to the fact that I was a genius. The man say, ‘we got all that we can use.’ Now I got them steadily depressin', low down mind messin working at the car wash blues.”
Thanks Jim Croce, but curses to you wrasse blenny. You almost messed up a great story, and added fuel to the popular belief that the high concentrations of nitrogen experienced by frequent scuba divers have a dampening effect on already limited mental acuity.
For more on cleaning stations see: http://www.wisegeek.com/in-a-reef-what-is-a-cleaning-station.htm
Details on the wrasse blenny can be found at: http://www.fishbase.org/summary/3727
Cutline: A parrotfish stops by a cleaning station off Key Largo. (Photo by Don Rhodes)