Labroides dimidiatus (Cleaner Wrasse) 

Photo : A Labroides dimidiatus cleaning a maroon clownfish.

This is the genus of obligate Cleaner Wrasses most celebrated for establishing stations in the wild that are frequented by "local" reef fishes and pelagics for removing parasites and necrotic tissue. Perhaps shocking to most aquarists, all the Labroides rate a dismal (3) in survivability, even the ubiquitously offered common or Blue Cleaner Wrasse, Labroides dimidiatus. None of the Labroides should be removed, not only for the fact that almost all perish within a few weeks of wild capture, but for the valuable role they play as cleaners.

Let's get to the fishes to avoid for this installment, and the rationale, or at least offer you my opinions on what it might take to keep them successfully for those who can't be outright dissuaded in their use.

The wrasse family Labridae is well known to aquarists. They are common, often colorful marine reef fishes of the Atlantic, Indian and Pacific Oceans. This is one of the most diversified of all fish families. Size spans a few inches to nearly ten feet; (Cheilinus undulatus, the Napoleon) now, that's a wrasse!

Like the freshwater cichlids, wrasses have protractile mouths, a feature affording great flexibility in prey range and manipulation. There are some four to six hundred legitimate described species; the variable number due to oft-made discoveries of amazing range of structure and color within a species on the basis of sex and size. Check out the photo offerings in Burgess, Axelrod and Hunziker's Atlas of Marine Fishes pages 423-477 for examples of striking differences between juveniles, adults, males and females. Things get even more bizarre when you consider that many wrasses are known to change sex, and that internal physical/structural changes parallel external appearances. Some ichthyological anatomists have likened the diversity in the morphology of wrasse skulls to that of all the bony fishes combined. Take a look at the jaws of California's own Sheephead, Semicossyphus pulcher.

On with the issue at hand. One of the wrasse family's fifty eight genera is Labroides, with five described species. The most commonly available is the black, blue and white lined Labroides dimidiatus; the other four have other colors, cost much more money (a few to several tens of dollars U.S.) and should not be offered to the hobby, or encouraged to be so by their purchase.

Symbiosis: Remember that fancy scientific word for "living together"? Symbiosis, oh yeah. As you'll recall there's all sorts of terms describing kinds and degrees of symbiosis; parasitism, mutualism, etc. depending on who's doing what to whom to whose benefit(s).

Cleaning symbiosis involves two different species getting together for mutual advantage, the host having parasites and necrotic tissue removed, the cleaner deriving nutrition and probably protection from predation (just try taking those two wrasses from that moray). Cleaners are further classified as being obligate or facultative. Facultative cleaners do their cleaning and therefore nutrition more or less as a sideline, able and willing to seek other non-parasitic food sources. There are many examples of these facultative part-timers; several angelfishes and butterflyfishes as juveniles, the senorita wrasse (Oxyjulis californica), the chromide cichlids (sic Etroplus).

Obligates: Obligates by definition get all or virtually all their nutrient from their cleaning activity; various species setting up permanent cleaning stations with "customer" hosts coming in for regular grooming. Experimental removal of some of these cleaners has demonstrated their immense importance as parasite controls. Local and even large pelagic fish populations are quickly negatively impacted by their removal. Fish populations drop or migrate and remaining fishes lose fitness as measured by increased external parasite loads, sores and torn fins.

Casual diving with the four multi-colorful Labroides species reveals that they are of limited numbers and closely defined distribution. When they are removed, the whole reef population suffers.

Further, these species have not been kept for any length of time in captivity, most dying within a few days to weeks due to a lack of nutritive interaction with host fishes. I have heard stories and seen the endemic Hawaiian cleaner, Labroides phthirophagus accepting dry prepared, freeze-dried, fresh and live foods, still only to waste away and die.

If you want to "practice" on cleaner wrasses, the blue, black and white lined Labroides dimidiatus is the one species that seems more facultative. If you're just looking for a biological cleaner for their services or novel behavior, please consider shrimps in the genera Hippolysmata, Periclemenes, or cleaner gobies. They do the job and do well in captivity, with much less deleterious effect on being removed from the wild.

Imagine going into town for a haircut, a manicure, for medical or dental care only to find these personal services unavailable because some foreign species has hauled off all the providers... Or visualize that you're furnishing these dispensations and now instead of innumerable customers you're translocated to where there are a mere handful. You'd be bugging them all the time, to their annoyance.

Think about this every time you cast your vote by buying livestock at the fish store. The obligate cleaner Labroides wrasses should remain in the ocean, and you should knowingly spend your money on hardier species.

With the permission of Robert (Bob) Fenner webmaster of WetWebMedia (bobfenner@aol.com)