I am utterly fascinated by cleaning stations – I’ve seen a few small cleaning stations, but since I’ve mostly only dived in guided groups, they tend to break up fairly quickly at the approach of noisy, bubble-belching giants. The best cleaning station action I’ve been able to see so far has been while snorkeling.
These photos of an Initial Phase Queen Parrotfish being cleaned (most likely) by juvenile bluehead wrasse are the best we’ve ever gotten of cleaner fish in action. At the time, I didn’t even know what I was looking at. It wasn’t until later when perusing the fishinar archives on Reef.org that I came across a fishinar presentation “Cleaning Stations” given by Ned Deloach (co-author of everyone’s favorite fish ID books) that I really began to understand the importance of cleaning stations and the amazing relationships that play out there.
Cleaning stations serve an incredibly important role on the reef. A number of studies (past and ongoing) have demonstrated that the biodiversity and overall biomass on the reef as well as the health and fitness of individual fish rely heavily on the services provided at cleaning stations. There are some specially exciting research projects being conducted on the Great Barrier reef by the Coral Reef Ecology Group.
The fish who come to be cleaned are generally referred to as Client fish and the fish doing the cleaning are called cleaner fish. However, both client and cleaner are general terms for the role and can be filled by a number of different species of fish. Groupers, Moray Eels, and Goatfish are a few examples of common client fish species. Cleaner fish are mostly comprised of the juvenile fish of the species most commonly found on the reef – Bluehead wrasse are among the most common in the Caribbean, but several other species can also be observed cleaning. Other cleaners include several shrimp species and a few specialized adult fish species.
Below is a diagram of the most common ecto (external) parasites that will attach themselves to fish and drink their hosts’ blood. Fish come to cleaning stations to get these parasites removed by small fish. If you are very patient and still, you can see the tiny cleaners darting in and out of the mouths and under the operculum (gill covering) of larger fish and eels to get at the parasites lodged in the soft, blood-rich tissues of the gills.
A client fish will often signal a desire for cleaning by hovering near the reef in a nose up or nose down position with mouth open and fins spread – as is the case in the pictures we got of the Queen Parrotfish. Some fish will also change to a darker color – there is speculation about the purpose of this – a darker color may signal readiness for cleaning, or maybe the darker color provides better contrast for displaying the parasites – making it easier for the cleaners to find and eat them.
Cleaners can also signal availability to potential client fish. Some species of shrimp – such as the Pederson cleaning shrimp – will wave their antennae around and “dance” up and down to attract attention.
Ned Deloach has studied cleaning stations for many years and has some truly amazing photos and stories of cleaning stations in action. He tells a story about a viper moray to illustrate another important role that cleaning stations fill – wound healing. Wounds under water can get infected and become deadly very quickly. The viper moray in his story has a serious injury that he got cleaned every day for three days – the cleaning made visible improvement on the wound and by the 3rd day, it was almost totally healed.
If you go diving along a coral reef, finding a cleaning station usually isn’t too difficult, but seeing it in action takes time and patience. Ned Deloach recommends finding a place in the sand to kneel down and wait without moving – maybe about 5 feet away. He recommends not looking directly at the fish – which can be perceived as threatening. It can take some time for cleaning activity to resume after an initial interruption, but if you are patient, it is well worth the wait!
After hearing this presentation, I feel totally inspired to try my luck at watching a cleaning station in action, next chance I get!
Deloach, Ned. 5/15/2013 8:00pm PDT. Fishinar presentation “Cleaning Stations” Hosted by reef.org https://www.reef.org/events/fishinar-cleaning-stations
Waldie, P. A., Blomberg, S. P., Cheney, K. L., Goldizen, A. W., & Grutter, A. S. (2011). Long-term effects of the cleaner fish Labroides dimidiatus on coral reef fish communities. PloS one, 6(6), e21201. https://doi.org/10.1371/journal.pone.0021201
Grutter, Alexandra, et. al. Cleaner Fish Do Clean! Coral Reef Ecology Group. http://www.cleanerfish.com/the-cleaner-fish-chronicles.html