The wrasse is a typically small & often colorful species of fish, found in the coastal waters of the world’s major oceans. The Cleaner wrasse is the most commonly known wrasse species as it is often seen alongside other marine animals, including sharks.
The Wrasse family is large, and diverse with more than 500 different species of Wrasse found in the shallower coastal waters and coral reefs, of the Pacific, Indian and Atlantic oceans. Wrasse most commonly inhabit areas that have an abundance of both food and places to hide, making coral reefs and rocky shores the perfect home for the wrasse.
Cleaner wrasse are the most well-known wrasse species and I’ll discuss these cool creatures in more detail after introducing you to some interesting Wrasse facts.
Some Interesting Wrasse Facts….
- Wrasse can reach 4 to 98 inches in length, depending on the species.
- The colour of the body depends on the species, habitat, age and gender. Wrasse can be white, yellow, orange, red, purple, blue, green, grey, brown or black and covered with numerous bars, stripes and markings.
- Wrasse have a pointed snout, thick lips and prominent (outward oriented) canine teeth. They have an elongated body covered with smooth scales and long dorsal and caudal fins.
- Wrasse are diurnal fish (active during the day).
- Wrasse are carnivores (meat-eaters). Their diet is based on small invertebrates (crabs, shrimps, mollusks, snails and sea urchins) and fish. Wrasse occasionally follows large marine predators and collects leftovers of their meals.
- Natural enemies of wrasses are lionfish, barracuda and sharks.
- Wrasse can bury itself in the sand or quickly swim away (thanks to well developed pectoral and caudal fins), to escape from predators. Some species hide among the large tentacles of mushroom coral and sea anemones.
- Wrasse can be part of large schools (group of fish) or live solitary lives.
- Wrasses can become solitary, aggressive and territorial when they reach adulthood.
- Spawning season of wrasses takes place all year round in tropical waters or during the warm period of year in subtropical and temperate areas.
- Some wrasses are born as females, but they change sex and transform into males later in life. These individuals are scientifically known as sequential hermaphrodites.
- Females produce and release thousands of eggs during the spawning season. Some wrasses show parental care. Males guard eggs laid in the algae or various cavities until they hatch. Other species of wrasse produce planktonic eggs which freely float, carried by ocean currents. Incubation period lasts 24 hours on a temperature of 27 degrees Celsius (lower temperature prolongs incubation period).
- Wrasse can survive 3 to 30 years in the wild (most species live from 3 to 5 years).
- Cleaner wrasse (species of wrasse) collects and eats dead tissue and parasites accumulated in the mouth of large marine fish.
The Cleaner Wrasse
The five species of cleaner wrasses of the genus Labroides are truly an interesting group of fish. While not a unique behavior in the underwater world, their pathogenic cleaning service is quite remarkable. The Bluestreak Cleaner Wrasse is typically a small sized fish with the average length being about 11 cm (4″) long.
Although they are small, they sure do lead an interesting life. For starters this tiny fish is a carnivore which feeds upon parasites and dead tissue of larger fish. This creates a perfect mutualist relationship between the Wrasse and the fish it is living off of.
In this case the Bluestreak Cleaner Wrasse gets to eat and is protected by the larger fish while the host receives all kinds of health benefits from the Wrasse. The larger fish usually recognize the Bluestreak Cleaner Wrasse by their lateral stripe running down the length of their body.
Once the larger fish has the attention of the Wrasse they will strike a species specific pose which allows the Wrasse access to their body surface, gills and even their mouth. That cleaner fish would have to be brave to go towards the mouth of a potential predator.
These small, busy fish set up ‘stations’ in a part of the reef, in which a pair or harem diligently clean parasites, dead and damaged scales, and mucus from bony fishes, sharks, and sea turtles that present themselves for cleaning.
A number of scientific studies and research attest to the important role these fish play in the health of the reefs. The overall health, size, and even diversity of fishes is greater in the reefs where cleaner wrasses are found versus those without their services.
The feeding behaviour of the Cleaner Wrasse is interesting but nowhere near as interesting as their unique social behaviour. Basically all Bluestreak Cleaner Wrasse begin their life as females. In a group of 6 to 8 Cleaner Wrasse there is usually only one male while the rest are females or juveniles.
So if they all begin life as a female, how do you get males?
This is a good question and the answer is they practice sequential hermaphroditism. All this means is once the male dies, the strongest female will simply change her sex and become the new male. The Cleaner wrasse really is an interesting and significant part of our underwater ecosystem.
Next time you go scuba diving I’m sure you will encounter one helping clean other fish or perhaps even help clean you! Be sure to say hi to these nifty little critters.
Author: Niek van Riel (PADI MSDT #344046)