Anthias are some of the hottest fish in the modern reef aquarium trade. They max out atmanageable sizes, shoal in radiant colors and many species are reef safe. Though some ‘staple’species have been long-present in the hobby, new species of anthias are being discovered in thewild each year. Even with all the excitement, all species of anthias offer significant husbandrychallenges.Mostspecieshavecomplexsocialhierarchiesandmanyliveindeepwaterreefslopes which are difficult to simulate in aquaria. Anthias also have fast metabolisms and requirenear constant feeding on copepods and other microcrustaceans. They also require their live feedsto be rich in polyunsaturated Golden Fats, otherwise their color and health will wane. In pastdecades,these magnificent fish all too often starved to death in captivity, but now that their needs are better known, aquarists can provide their anthias with swarms of pod-based nutrition!
Anthias belong to the Serranidae family and are relatives of grouper, sea bass and basslets. The Anthiinae subfamily has a good deal of variation, but reef fish broadly recognized as ‘Anthias’belong to the genera Anthias, Pseudanthias, Odontanthiasand Serranocirrhitus. In the wild,these species usually occupy reef slopes and mingle between the photic zone and the dark depths.For example, shoals of Pink Square Anthias (Pseudanthias pleurotaenia) can be found at depthsof 30-50ft as well as 200-600ft! There is an extreme difference in light availability at depth and itstands to reason that many anthias may not be well suited to the high-intensity full-spectrumlighting of an Acroporadisplay aquarium. However this is more true for some species thanothers. Shallower-wateranthias species such as the Lyretail Anthias (Pseudanthias squamipinnis)and the Red-Lined Anthias (Pseudanthias fasciatus) frequent reef shallows and therefore aremore accommodating to ‘standard’ reef aquarium lighting. Deeper water species such as theAuroraAnthias(Pseudanthiascalloura)routinelyinhabitdepthsexceeding150ft.Thispresentsa profound challenge to find lighting schedules, flow patterns and novel tank designs which bestcater to the needs of deepwater anthias species.
In the wild, anthias are ravenous planktivorous, feasting on the constant myriad of copepods,rotifers, fish eggs and mixed larvae descending down reef slopes. The gastrointestinal systems ofthe serranidae featurea largecardiac stomach.This iswhat allowsgrouper andsea bassto eatand digest large prey items. The gastrointestinal systems are slightly modified in anthias in thatthey have a smaller cardiac stomach and faster metabolism than other serranids. Unlike a grouperwhich can consume a moderate-size fish and be satiated for days, anthias are designed tocontinuously snatch high value prey items such as copepods, fish eggs/larvae and large marinesnowdescendingfromtheupper reef.Thisiswhy itisabsolutelyvitalthat anthiasbehousedinawell-established reef aquarium that is constantly producing excess microinverts. That being said,even a few anthias can exhaust the copepod population of an open reef--making it all the morebeneficial to supplement tanks with copepods and to establish biocomplex refugiums. Refugiums well stocked with Sea Veggies (Ulva, Chaetomorpha, Gracilariaetc.) not only assist inmaintaining the pristine water quality needed by anthias but foster immense colonies ofcopepods, isopods, amphipods, snails, polychaete worms and other invertebrates. It is bycontinuouslydosingmicrocrustaceansandtheeggs/larvaeofotherrefugiumcleanupcrew,thatanthias may receive a fraction of the infinite microprey they enjoy in the wild.
There are countless reasons why copepods such as the cyclopoid Apocyclops panamensisas wellas the harpactoids Tisbe biminiensisand Tigriopus californicusare suitable live feed for manyAnthias species:
- TheypossesbodytissuesrichinPUFAs(ARA/EPA/DHA),proteases,probiotics,prebiotics and enzymes
- They are soft-bodied with no hard protrusions or indigestible shells
- Adult copepods ‘pep’and ‘scoot’in between surfaces, makingthem highly attractive topredators.
- Colonization of an aquarium with a robust copepod population will provide constantnutritious grazing opportunities.
- Copepods consume uneaten feed, algae, bacteria and feces--reconverting these wastesinto a constant surplus of Golden Fat Live Feeds!
The embrace of copepods in ornamental aquaculture has allowed for the captive rearing of ahandful of Anthias species. Anil et al 2018 was able to successfully spawn wild caught Marcia’sAnthias (Psuedatnthias marcia). The resulting larvae were successfully reared on a mixture ofrotifers (Brachionus rotundiformis), pelagic copepod nauplii (Parvocalanus crassirostris), wildzooplanktonandformulatedmicrodiet.Thekeytothisapproachistoprovidethemicro-mouthedlarvae with as many Golden Fats (ARA/EPA/DHA) as possible while at the same time, seedingtheir guts with probiotics, prebiotics, proenzymes and proteases. Similar techniques have madecaptive-bredBlotchedAnthias (Odontanthias borbonius) available to the hobby. Even industry-staple species such as the Lyretail Anthias (Pseudanthias squamipinnis)have been bredexperimentally, yet not nearly in commercial quantities. But these are recent accomplishmentsand for the most part, aquacultured anthias are still decades in the making. This is franklybecausetoolittleisknownaboutthewildbiologyoftoomanyanthiasspeciesinthehobby.Untilmore of their natural mystery is revealed, anthias aquaculture will be a series of very steep hills.
There is of course one more confounding factor to anthias husbandry. Anthias shoals operateunder a nuanced and complex social hierarchy which determines the sex, size, appearance, andbehavior of the individuals within it. Anthias are sequential protogynous hermaphrodites,meaning that they first sexaully mature as females then can further mature into males. In thewild, many anthias species operate in functional harems where a single male ‘rules’ a series offemales and sometimes subordinate males. Anthias males often have completely differentcolorations and much more pronounced fins than females. If a dominant males is removed orkilled,thelargestofthesubordinatemales/femaleswillundergoahormonalshiftandadoptboldmale features. Forming a stable harem group is paramount to keeping anthias in an aquarium ascompeting males will often fight, resulting in chronic stress and death. Stable harem sizes andratios vary with species and likely environment. Anikuttan et al 2017 reported that wild LyretailAnthias (Pseudanthias squamipinnis) usually exhibited functional harems consisting of 8females to every dominant male. Anil et al 2018 reported spawning behavior by Marcia’sAnthias(Pseudanthiasmarcia) byfunctional haremsconsisting of7 femalesto every5 males. Besides the crude ratio of males to females, there is an incredible degree of nuance and variationtoanthias social dynamics and breedingbehaviour
In conclusion, there is far more refinement to be had in the realms of anthias husbandry andaquaculture. Even though a handful of species have been bred in captivity, dozens more remaindifficulttoevenkeepalivewhilecountlessothersremainundiscoveredaltogether.Sofaranthiashusbandry principles are such:
1. Possessthelargestandmostvertically-complexaquariumpossiblesoasto MimicaReefSlope.
2. Provide continuous grazing opportunities for suspended copepods and other microinverts richinGolden Fats (PUFAs).
3. Be ever mindful of anthias social hierarchy and attempt to establish a Stable Breeding Harem.
There is a reason why so many aspire to keep anthias in the reef aquarium hobby. For manydivers, expansive shoals of anthias radiating color down a reef slope is a breathless site. Thissubfamily has some of the most charismatic colorations of all reef fish and this combined withtheir spunk, their mystique...how could anyone be blamed for wanting such beauty for theirhomereef?Thoughfarfromasimpletask,thefrontierofanthiashusbandryisever-expanding,and ever-more possible by the commercial-scale cultivation of copepods and other Golden FatLive Feeds!
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