Some fish shouldn't be kept in aquariums. Cleaner Wrasse should be at the top of this list due to their poor survivability rate and importance in keeping the worlds reefs healthy. While it's understandable that people want to see as much natural behaviour in their tanks as possible, the actions of a cleaner wrasse seems to be one of the more destructive symbiosis to attempt to reproduce, especially when there more suitable fish that demonstration the same symbiotic relationships.
Currently there are six different species of cleaner wrasses that have been identified. The most common one offered for sale is the Common or Bluestreak Cleaner Wrasse (Labaroides dimidiatus) due to it's striking colouration, closely followed by the more rare Hawaiian Cleaner Wrasse. While there are other types of wrasse that are referred to as cleaners and do perform some cleaning services, unless they are of the genus Labroides they aren't the true Cleaner Wrasses.
Cleaner Wrasse setup cleaning stations that generally consist of at least two fish. A cleaning station is a place that many different species of fish (called clients) congregate in order to have parasites removed. When the clients approach the cleaning stations their behaviours change, they tend to swim in a more vertical position, spread their fins and operculum out and even alter their colouration slightly. This allows the cleaner wrasse better access to the entire client being inspected for parasites. While at a cleaning station, fish that are generally aggressive tend to turn off their natural instincts and not eat the cleaner wrasse, they even allow the cleaner wrasse to swim into their mouths with little fear of predation.
In the wild, the vast majority of the parasites that cleaner wrasse eat are small crustaceans called gnathiid isopods. The isopods live in the rocky crevices of the reefs where it is difficult for fish to prey on them. While the adult forms of the gnathiid isopods do not feed on fish, the juveniles do. They make frequent trips from the rocks onto fish where they bite the fish in order to feed on blood. These young isopods can feed on many fish through it's life time and can carry potentially dangerous diseases of the blood, similar to the way mosquitoes transport diseases in humans. If left unchecked there would be a pandemic in the reef fish population as blood diseases would be able to spread quickly.
Each cleaner wrasse can eat over 1000 of these gnathiid isopods each and every day. When cleaner wrasse are removed from an area the numbers of gnathiid isopods in that area can increase drastically in a short period of time. When this happens fish start to migrate to different areas where the isopod population is more tolerable and the fish can be cleaned when needed. Eventually if enough cleaning stations are removed, the vast majority of fish in that area disappear and what was once a healthy ecosystem becomes a barren waste-land.
Scientists also use cleaner stations to make it easier to see the diversity of fish on a reef. Since nearly all fish will eventually stop in at a cleaning station and the cleaning stations remain relatively stationary, it's easy to set up an observation post and count the number of individuals and species of fish that stop in. Scientists have discovered that the number of individuals and diversity of species in an area noticeably drops when even a few near-by cleaner wrasse were removed.
There are no cleaner wrasse in the Atlantic Ocean, they are all found from the Red Sea to the Pacific. In the Atlantic Ocean similar cleaning services are performed by the Cleaner Gobies. Interestingly enough, in an aquarium setting fish from the Atlantic can recognise and utilize a cleaning station serviced by cleaner wrasse and fish from the Pacific will utilize the cleaner gobies services even though these fish would never come into contact in the wild.
The difference between cleaner wrasses and any other type of wrasse that perform cleaning services is that members of the genus Labroides are obligate feeders whereas the others are facultative feeders.
Facultative feeders are fish that can feed on a wide variety of foods and are able to get the nutritional benefits from many different sources. Most other fish and invertebrates that perform cleaning services are facultative feeders and only perform cleaning functions are a supplement to their diets. This gives them a much greater advantage in captivity since they can benefit from supplemental feedings while in an environment that may not have enough of the specialized foods for obligate feeders to consume.
Obligate feeders only feed on a very specific diet. In the case of cleaner wrasses, this diet consists of common parasites found on reef fish. Without a steady diet of these parasites the fish will starve to death. Even if it is offered and accepts alternative foods it doesn't get all the nutrients that it requires to survive and will slowly starve to death. Cleaner Wrasse feed on ectoparasites (parasites that live on the outside of a fishes body such as isopods, and sea lice) mainly gnathiid isopods. Although they do ingest mucus and scales from fish as they are feeding it is unknown how important these elements are to their nutritional needs.
One of the most commonly stated reasons for someone getting a cleaner wrasse for their tank is to help combat the most common parasites which are Cryptocaryon irritains (Ich) and Amyloodium sp. (Marine velvet). While these two diseases are extremely common in aquariums, they only occur infrequently in the wild. This means that it is very unlikely that cleaner wrasse have evolved to be able to acquire many nutrients from these two parasites. Secondly ich has a tendency to bury itself under the skin of the fish they are on until it is ready to fall off. This makes it very difficult for the cleaner wrasse to clean the parasite off an animal until the damage is already done.
To make matters worse, the cleaner wrasse is not immune to these common aquarium diseases so adding the cleaner wrasse to an infected tank will only subject them to the infestations as well
One of the most devastating events to have occurred in recent times where Cleaner Wrasse are concerned is the advent of the internet and more specifically forums dedicated to keeping marine fish. While the internet and forums are generally a source of very helpful information there are times where the advice and information being given is less then ideal. In nearly any forum I have visited (and I have visited a lot of them) there is bound to be a thread in regards to someone wanting/having a cleaner wrasse quickly followed by false or inaccurate information. The main responses given to any sort of attempt to discourage people from acquiring a cleaner wrasse are "they can adapt to other foods" and "I've had mine for months without any problem." These statements are very misleading as the vast majority of cleaner wrasse starve to death within the first weeks of being in captivity and it's mostly the owners of the that survive for any length of time or those who just acquired specimens who reply to these threads.
Many online and local retailers who sell cleaner wrasse offer them as inexpensive fish and don't offer any sort of guarantee on them. This is because they know that they need to get it out of their store as quickly as possible so they can get their money's worth from them before they starve to death and that the people they are shipping them to wont have very much luck in keeping them alive.
Don't buy them:
One of the most effective methods we have available to help stop the collection and sale of cleaner wrasse is our pocket book. If enough people refuse to buy them then there is no profit for a store to order them. Even stores with the most ethical stances will stock them if there is a great enough demand because if they don't, someone else will. It's up to us to stop this demand.
Spread the word to discourage others from buying them:
Another simple effective way to help stop the collection of these vital animals is to educate people around us and other hobbyists about their importance and poor survivability in captivity. We need to put pressure on fellow hobbyists to prevent them from buying them as well.
Use alternative animals that perform the same services:
There are many animals that will show very similar symbiotic cleaning relationships that are a lot more suitable for the aquarium then Cleaner Wrasse such as Shrimp and Cleaner Gobies.
Scarlet cleaner shrimp, Lysmata debelius
Cleaner Shrimp are shrimp from the genus Lysmata or Periclimenes. The two most common cleaner shrimp available are Lysmata amboinensis (Skunk Cleaner Shrimp) and Lysmata debelius (Blood Cleaner Shrimp). Cleaner Shrimp are readily available, relatively hardy and have been bred in captivity. They are good for removing parasites from fish. Since they are crustaceans, they don't suffer from the same aliments such as ich or marine velvet like fish do. However they can't be kept with fish that normally eat crustaceans such as lionfish or trigger fish. Cleaner Shrimp do not tolerate medications very well.
Cleaner Gobies are gobies from the genus Elacatinus (Formerly Gobiosoma). The most common cleaner gobies offered are Elacatinus oceanops (Neon Cleaner Goby ) and Elacatinus randalli (Yellow-nose Cleaner Goby). They are just as good as the cleaner wrasse for observing a symbiotic relationship and they don't need the specialized diet. They are very hardy and will even breed in the aquarium. A lot of the individuals offered for sale are captive bred so the balance of delicate ecosystems aren't upset. These hardy fish remain small and readily eat regular fish food. The main draw back is that they suffer from the same ailments as any other fish in the tank so you need to avoid adding healthy individuals when there is an outbreak of diseases such as marine velvet or ich.
Juvenile Angelfish have been observed performing cleaning services on other fish on the reef. Some juveniles continue to clean fish in captivity and are more hardy then cleaner wrasse. Juveniles tend to adapt better to captivity as well. The main disadvantage to relying on juvenile angelfish is they tend to out grow the cleaning stage. Also many angelfish grow fairly large so it's important that the tank they are to be housed in is large enough for the adult. A second disadvantage is angelfish can take a liking to corals so use caution and do some research before buying.