DAVE WOLFENDEN

Cleaner wrasses are the der­ma­tol­o­gists, beau­ti­cians and masseuses of the reef. But are they re­ally suit­able for cap­tive care? We look at the ar­gu­ments for and against keep­ing th­ese re­mark­able fish in a mixed aquar­ium.

Practical Fishkeeping (UK) - - Welcome - WORDS: DAVE WOLFENDEN

is cu­ra­tor at the Blue Planet Aquar­ium in Cheshire Oaks. He looks at the ar­gu­ments for and against keep­ing Cleaner wrasse.

Cleaner wrasses of­fer an im­por­tant ser­vice to other fish in the wild, in­clud­ing re­mov­ing dead skin and pick­ing off isopods, flukes and var­i­ous other ec­topar­a­sites, all to the greater good of the reef.

In the aquar­ium they can pro­vide clear ben­e­fits, but in the wrong sys­tem they are a poor choice due to their chal­leng­ing na­ture. Hav­ing said that, the ap­pear­ance of cap­tive-bred spec­i­mens means that we may be look­ing at sus­tain­able and much less de­mand­ing an­i­mals in the fu­ture.

The Bluestreak cleaner wrasse

The Bluestreak, Labroides dimidia­tus, is prob­a­bly the de­fin­i­tive cleaner wrasse for most aquar­ists. Wide­spread around the Indo-pa­cific, it reaches around 10cm/4in in length and sports a dis­tinc­tive ‘cleaner blue’ colour. On the reef, L. dimidia­tus is ter­ri­to­rial, and pairs or groups es­tab­lish clean­ing sta­tions which are vis­ited by client fish for re­moval of par­a­sites, loose and dam­aged scales, and dead skin. Pro­vid­ing a good ser­vice means re­peat busi­ness with clients re­turn­ing to their pre­ferred cleaner.

The Bluestreak cleaner is by far the most com­monly-of­fered species and the least dif­fi­cult to care for — but that’s rel­a­tively speak­ing; it still presents chal­lenges. While it can be trained to ac­cept pre­pared foods, th­ese should only be viewed as sup­ple­men­tary, and the wrasse’s ap­petite for clean­ing can cre­ate is­sues.

A study by Alexandra Grut­ter of James Cook Univer­sity in Queens­land re­vealed that Bluestreaks are prodi­gious clean­ers, con­sum­ing around five par­a­sites per minute and deal­ing with over 2000 client vis­its per day! And cleaner wrasses don’t just feed on par­a­sites: they will ‘cheat’ by pref­er­en­tially feed­ing on fish mu­cus and skin, as this gives a nu­tri­tional boost (at a cost to the client). On the reef, they tend to do this if they can get away with it, so they ap­pear to cheat her­biv­o­rous clients rather than preda­tors ca­pa­ble of eat­ing them. They will also tend to cheat more fre­quently when par­a­site load­ings are low within their client base.

What this means is that the sys­tem must be right for th­ese wrasses to thrive. They can be bril­liant in large sys­tems with suf­fi­cient num­bers of client fish. Given enough space, it’s pos­si­ble for one or two wrasses to es­tab­lish a clean­ing sta­tion which their clients can visit when they wish (and es­cape if they need to) — and if the tank is suit­ably stocked, the clean­ers won’t tend to fo­cus their at­ten­tion on a small num­ber of clients.

Put them in a small tank with just a few fish, how­ever, and they can be a pest, con­stantly ha­rass­ing their tank mates and dam­ag­ing them through their in­ces­sant peck­ing. Ide­ally, you’re look­ing at a sys­tem of 1000 l or more, jam-packed with fish.

Per­sonal ser­vices

We all know that a mas­sage is a great way to de-stress. Cleaner wrasses of­ten en­gage in pre-clean­ing ‘mas­sages’ by rub­bing clients with their pec­toral and pelvic fins. This tac­tile stim­u­la­tion ap­pears to be ben­e­fi­cial to the client fish. Pre­sum­ably it helps build up trust be­tween cleaner and client, but it also ap­pears to re­duce stress lev­els in the client. This was demon­strated in an in­ge­nious 2011 study* by Marta Soares and her col­lab­o­ra­tors.

Two types of model cleaner wrasses were made separately avail­able to Sil­ver spot tangs, Ctenochaetus stria­tus. Both mod­els were iden­ti­cal — each type was painted to re­sem­ble a Bluestreak cleaner wrasse and had soft bris­tles — where the dif­fer­ences lay was that one was mov­ing cour­tesy of a me­chan­i­cal rocker;

the other type was sta­tion­ary.

The tangs with the mov­ing mod­els spent much more time with them than those with the sta­tion­ary ones; this in­cluded pos­ing, touch­ing and phys­i­cally in­ter­act­ing with the mod­els. Soares then ex­am­ined the stress re­sponses of the tangs by mea­sure­ment of the hor­mone cor­ti­sol, in­clud­ing con­fined (stressed) and non-con­fined (non­stressed) fish. The re­sults re­vealed that tangs which in­ter­acted with the mov­ing mod­els had lower cor­ti­sol lev­els (and there­fore lower stress re­sponses) than those with ac­cess to sta­tion­ary mod­els. Not only that, when sub­jected to con­fine­ment in a bucket, fish which had pre­vi­ously in­ter­acted with a mov­ing model demon­strated a lower stress re­sponse.

The study pro­vides strong ev­i­dence that di­rect phys­i­cal con­tact of the kind pro­vided by cleaner wrasses is ben­e­fi­cial for reef fish (Soares sug­gests that the mas­sages are of­fered as a trade-off by the cleaner to off­set the ef­fects of cheat­ing). What­ever the rea­son, it seems that the mas­sages pro­vide a tan­gi­ble ben­e­fit to their tank mates in the form of re­duced stress. It’s pos­si­ble that ad­ding a cleaner to the aquar­ium could pro­vide the same ben­e­fit, but this needs to be bal­anced against whether they have a choice to in­ter­act with the cleaner or not.

Hawai­ian cleaner wrasse

The Hawai­ian cleaner wrasse, Labroides ph­thi­roph­a­gus, is a gor­geous species, with its golden an­te­rior half and bright vi­o­let tail mark­ings. It reaches around 10cm/4in in length and is en­demic to the Hawai­ian re­gion. In the wild, this is an ob­li­gate cleaner, re­ly­ing on a diet of par­a­sites and fish mu­cus; with­out suit­able num­bers of clients in the aquar­ium, it is very dif­fi­cult to main­tain. Al­though wild-caught L. ph­thi­roph­a­gus are very chal­leng­ing fish, in 2016 Avier Mon­talvo bred the species at Ris­ing Tide Con­ser­va­tion in Hawaii. This was ini­tially un­in­tended, when a pair of the wrasses spawned in a sys­tem hous­ing brood­stock in­clud­ing tangs and but­ter­flies. Avier has now bred the species twice, and his ex­pe­ri­ences sug­gests that if the fish are raised on pre­pared di­ets they can ef­fec­tively be con­di­tioned to be­come fac­ul­ta­tive clean­ers (mean­ing they don’t rely on clean­ing alone to meet their nu­tri­tional needs), mak­ing them po­ten­tially more suit­able for aquaria. This is game-chang­ing stuff. The im­pli­ca­tions for con­ser­va­tion are ob­vi­ous, but it also il­lus­trates how cul­tur­ing such chal­leng­ing species can ad­dress many of the dif­fi­cul­ties as­so­ci­ated with their long-term care. No­body’s sug­gest­ing that cap­tive bred Hawai­ian cleaner wrasses are sud­denly ‘be­gin­ner’ fish, but they cer­tainly look more vi­able for aquar­ium life. While we aren’t at the stage where cap­tive-bred cleaner wrasses out­num­ber their wild-caught coun­ter­parts in the trade, Ris­ing Tide’s Hawai­ians have been made avail­able to North Amer­i­can hob­by­ists through Los An­ge­les­based Qual­ity Ma­rine. This is one of many Ris­ing Tide breed­ing projects the com­pany sup­ports, with an im­pres­sive list of species which in­cludes the Mil­let­seed but­ter­fly­fish, Chaetodon mil­iaris; Re­gal tang, Para­can­thu­rus hep­a­tus; Me­la­nu­rus wrasse, Hali­cho­eres me­la­nu­rus; Yel­low tang, Ze­bra­soma flavescens, and the Yasha goby, Stono­go­b­iops yasha.

Has the feed­back been pos­i­tive re­gard­ing the cap­tive bred clean­ers? “Qual­ity Ma­rine Ac­count Man­agers have re­ceived noth­ing but great feed­back from the cus­tomers that pur­chased the cap­tive bred cleaner wrasse, which I think made this project even more suc­cess­ful,” Cyn­thia Delillo of Qual­ity Ma­rine ex­plains. “Tra­di­tion­ally, this species has been con­sid­ered sen­si­tive and chal­leng­ing, and es­pe­cially dif­fi­cult to feed prop­erly. Ris­ing Tide’s cap­tive bred ones are reared on read­ily avail­able di­ets, and don’t have th­ese same feed­ing is­sues, which was very at­trac­tive to our cus­tomers.”

Cyn­thia feels that aqua­cul­ture will play a de­cid­ing role in the fu­ture of the hobby — and ul­ti­mately, of the oceans them­selves, but price ap­pears to be a bar­rier at the mo­ment. “The in­creased costs as­so­ci­ated with cul­tur­ing th­ese species typ­i­cally re­sults in a more ex­pen­sive an­i­mal, which is not al­ways ac­cepted by hob­by­ists,” she says. “I do be­lieve that price will greatly de­ter­mine the fu­ture of aqua­cul­ture. Ev­ery­one in the in­dus­try needs to work to­gether to bet­ter ed­u­cate the public on the im­por­tance of aqua­cul­tured ma­rine or­na­men­tals and why they should choose a cul­tured spec­i­men.”

Bluestreak clean­ers have pre­vi­ously been cul­tured by Bali Aquarich with im­pres­sive re­sults, and Ris­ing Tide’s suc­cess­ful breed­ing of Labroides ph­thi­roph­a­gus ups the ante con­sid­er­ably. It does seem that cap­tive breed­ing is the way ahead here. Not only could we have fish that are eas­ier to keep, but we can be con­fi­dent that they are eth­i­cally sourced. There are con­cerns that re­mov­ing cleaner wrasses from the wild may im­pact on the health of fish on the reef; com­bine this with the gen­er­ally poor sur­vival rates of wild-caught clean­ers in aquaria, and it’s not a good look for the hobby. The know-how is there to breed them, so we can have them if we want them badly enough — and, cru­cially, are will­ing to pay a pre­mium for the priv­i­lege.

Eas­ier al­ter­na­tives

Al­though the prospect of cul­tured spec­i­mens will make them more ac­ces­si­ble, many sys­tems just won’t be suit­able for a cleaner wrasse. No cleaner is ever go­ing to be a ‘magic bullet’ to erad­i­cate dis­ease from the aquar­ium, but there are less chal­leng­ing al­ter­na­tives to cleaner wrasses that also of­fer ‘per­sonal ser­vices’ on the reef.

Of the nu­mer­ous cleaner shrimp species, the Scar­let cleaner shrimp, Lys­mata

am­boinen­sis, from the Indo-pa­cific is hard to beat. Reach­ing around 6cm/2.2in in length, with its red, white and gold stripes and dis­tinc­tive white an­ten­nae, it’s very at­trac­tive. This is by no means an ob­li­gate cleaner (and it also makes a great scav­enger), but given the op­por­tu­nity it will hap­pily primp and preen fishy clients. They can be kept in pairs in small tanks (and groups in larger sys­tems), and while rais­ing the young is a chal­lenge, they can be cap­tive bred. Be cau­tious if hous­ing them with large crus­tacean-munch­ing fish such as puffers and trig­gers, as they may find the shrimp too good to re­sist, par­tic­u­larly dur­ing moult­ing. As with all shrimp, ac­cli­mate ex­tremely slowly to pre­vent salin­ity shock. The At­lantic cleaner go­b­ies of the genus

Ela­cat­i­nus are also an ex­cel­lent al­ter­na­tive. The tiny 5cm/2in Neon goby, E. oceanops, from the Caribbean, is ar­guably the go-to species. It can be kept in pairs in tanks of less than 100 l, or in groups in larger set-ups, and can be cap­tive bred, too. They don’t rely on a diet of par­a­sites to sur­vive and hap­pily ac­cept a va­ri­ety of pre­pared foods, but will set up a sta­tion and per­form clean­ing du­ties if kept with other fish. Take care in tanks with preda­tory fish or larger crus­taceans.

FUR­THER READ­ING *Soares, M.C. et al. (2011) Tac­tile stim­u­la­tion low­ers stress in fish. Na­ture Com­mu­ni­ca­tions. 2:534

Bluestreak cleaner wrasse at work among the gills of a puffer fish client.

Phys­i­cal con­tact with cleaner wrasses has been shown to re­duce lev­els of stress in client fish.

Cleaner wrasse gets to work on a diver’s ear.

Ela­cat­i­nus go­b­ies will hap­pily set up a clean­ing sta­tion.

Neon goby, Ela­cat­i­nus oceanops.

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