Quintessential Small Polyped Stony Corals, the Staghorns, Family Acroporidae, pt. 3

/The Best Livestock For Your Reef Aquarium:

Quintessential Small Polyped Stony Corals, the Staghorns, Family Acroporidae, pt. 3

By Bob Fenner

One of two species in the Trop. W. Atlantic, off Bonaire

Genus Anacropora: Lack apical (growing tip) corallite. Irregularly branching, pointy slender (under 10 mm.) branches. Often encountered in sandy/muddy substrates. Anacropora are best described as arborescent (tree-branch like) Montipora without axial corallites (the fast growing polyp tips of Acropora). These are slow-growing, low color denizens of muddier, near shore environments of little interest to the aquarium trade. Six known species.

Genus Astreopora: Colonies are massive; maybe laminar or encrusting. Open polyps are large, resemble "jet engines". Have bumpy appearing, granular coenosteum

Astreopora, though frequently encountered in the trade is not a particularly hardy genus. Many possible causes have been cited for their common loss; lack of nutrient, chemical interactions with other inhabitants, cumulative damage from collection, handling and shipping... for whatever reasons we have found that these animals don't generally live, or if they do, grow slowly. Fifteen nominal species.

Astreopora myriophthalma (Lamarck 1816). Smooth, hemispherical colonies. Evenly spaced corallites that are exsert (pointed out) with rounded openings. Most common species. Red Sea images.

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The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.

Genus Isopora Studer 1878: Used to be considered a subgenus of Acropora. Have multiple axial polyps on the end of growing columnar or club-like branches; which are about 1 cm. thick.

Isopora palifera, (Lamarck 1816). Mabul, Saba, Malaysia. /COTW

Characters: Colonies are encrusting plates or thick ridges, columns or branches. Branches are usually upright, but are commonly horizontal or irregular in shape, depending on exposure to wave action. There are usually no axial corallites. Corallites are smooth, rounded and exsert. The coenosteum is composed of fine spinules with elaborated tips.

Colour: Pale cream or brown.

Similar Species: Isopora cuneata, which has smaller, flatter branches and finer, more rounded, less elongate corallites. These species are difficult to distinguish unless they occur together. See also I. elizabethensis.

Habitat: Occurs in all reef environments.

Abundance: The most abundant coral of the northern Great Barrier Reef where it is the dominant species of most exposed outer reef slopes. Usually less dominant elsewhere in Australia and most other countries.

Genus Montipora, very small corallites (under 1 mm.); most are laminar, encrusting, but there are upright branching, and columnar varieties. Often called "velvet" corals for their smooth appearance, are encrusting, plating and thick finger-like forms. For the family they are particularly hardy and fast growing for aquarists, warranting their great popularity. This genus' members especially need to be gradually adapted from lower to higher light conditions (placed lower-est in the system for the first few weeks) to avoid bleaching (loss of zooxanthellae). The eighty or so species of Montiporas are amazingly polymorphic and therefore difficult to identify by sight. They're often mistaken for Porites species and vice versa, but can be discerned when the polyps are retracted. The latter have numerous polyp skeleton internal structures whereas Montipora polyps are almost empty. (Images # Montiporas in the Red Sea and Hawai'i displaying inter-polyp 'hills' (papillae, tuberculae) typical of many members of the genus)(Images # .M. venosa, an exception to the 'possession of papillae and tuberculae rule' for the genus)


Montipora digitata in the P.I.	Montipora faveolata in the Red Sea	Montipora foliata

More Montiporas in Aquariums

Montipora cf. aequituberculata Bernard 1897.
http://coral.aims.gov.au/factsheet.jsp?speciesCode=0245 Bunaken/Sulawesi/Indonesia image.

Montipora caliculata, Mabul, Saba, Malaysia.

Montipora capitata (Dana 1846), Rice Coral. Encrusting to massive colonies to thin plates in calm water. Dark to light brown in color. Hawaiian endemic. Structural elements of polyps appear like grains of rice.

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Montipora confusa, Mabul, Saba, Malaysia.

Montipora danae, Queensland, Australia.

Montipora flabellata Studer 1901, Most colonies are fluorescent blue to purplish in color, though they can be brown. Shallow water (to 20 feet). Hawaiian endemic.

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Montipora cf. incrassata (Dana 1846), Fr. Polynesia 2018
http://coral.aims.gov.au/factsheet.jsp?speciesCode=0260

Montipora meandrina (Ehrenberg 1834). Colonies made up of irregular surface verrucae that aren't fused into a pattern. Shallow reef edge. Red Sea images.

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Montipora mollis Bernard 1897. "Colonies are irregular clumps, columns and plates. Corallites are mostly immersed, with fine but distinct walls. The coenosteum is coarse. Low tuberculae are sometimes present." Corallites under (on both sides) of plates. Tentative ID, Mauritius 2016.

Montipora monasteriata (Forsskal 1775). Colonies as massive encrusting forms or uni- or bifacial plates. Most corallites immersed; coenosteum covered with tuberculae or papillae. Light brown or blue in color with white margins. Common on upper reef slopes in its range. Red Sea images.

Montipora cf. aequituberculata Bernard 1897. Fr. Polynesia 2018
http://coral.aims.gov.au/factsheet.jsp?speciesCode=0245

Montipora tuberculosa (Lamarck 1816). Colonies submassive or laminar. Small corallites occur as both exsert and embedded, separated by papillae, tuberculae of a corallite width. Found in most reef types. Red Sea images.

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More Montipora Pix

More Montipora Pix

Selecting Specimens:

1) By sight: Examine the prospective buy carefully for uniform coverage of its skeleton by living tissue. Live acroporid polyps are a mere few millimeters deep and easily damaged in collection and shipping. There should be no tissue recession from the skeleton, or signs of bleaching (Image # . A captive-produced Acropora showing early signs of bleaching)

Polyp extension, not during day for newly arrived Acroporids, but towards the evening they should open, and most can be trained (by feeding) to open during the day.

There should be no algae growing on specimen. Filamentous algae growth is indicative of damage and weakness in a specimen, as well as poor husbandry conditions.

For Acropora spp., look for healthy growing tips; often pink/red, blue/purple in color. These tips often fade in transport and stress.

By smell. Healthy colonies are not malodorous; dead, dying ones stink. Viable Acroporids remind one olfactorily of terpenes, which they produce to chemically ward off other coral species.

Time on hand; the longer the better. Two weeks is a good interval to ensure that the animal has "made it" from the rigors of collection, through the maze of transport from the wild to your dealers.

Environmental Conditions:

Like corals in general and Small Polyp Stonies in particular, Acroporids require high, consistent water quality. Way before your fishes these stinging celled animals will herald declining bio-water quality. Look for signs such as non-opening polyps, the beginnings of filamentous algae... Some specifics of what these corals demand to do well:

High calcium concentration AND alkalinity; 400-500 ppm, 4+ milliequivalents/liter ideally. Best achieved through the use of ... proper/adequate filtration and a calcium reactor

Though there are plenty of species of Acroporids that dwell in deeper, quieter environments, most aquarium specimens are collected from exposed reef flats where constant, brisk water movement is the rule. Practically speaking you can't provide too much in the way of chaotic (i.e., non-linear) circulation. If you detect slime or debris on your corals, you're not moving your water enough.

Lighting, full spectrum, generally provided by VHO or compact fluorescents, or metal halides. Intensity should be low initially, either through manipulation of the source or placement of new specimens in deeper, darker parts of your system. Move up after a few weeks to a month. To accentuate growth, color and reduce nuisance algae growth use low UV and red-end spectra, high intensity 15-25k lux and up lighting.

Most Acroporids utilize overgrowing as their principal competitive strategy. Other corals are not so agreeable however. Space these fast growers a good 3 inches away from other hard and soft corals, and keep your eyes open for agonistic interactions. (Images # . With vigorous circulation hard and soft corals, including Acroporids can exist in the same system as shown in these images.)

Temperature and specific gravity should be steady. The former varies by species but a good range for Indo-Pacific species is the mid seventies to low eighties F, a few degrees cooler for the Tropical West Atlantic. Specific gravity is best kept in the 1.024-1.025 (a couple of thousandths higher for Red Sea biotopes) by daily checks and topping off.

It should go without stating, but there should be no detectable ammonia, nitrite, and little (less than 10ppm) nitrate. No useful phosphate will be present in systems with proper calcium concentration and alkalinity.

Tankmates. There are some small commensal crabs and worms, but most crabs are to be avoided as tankmates as are other corallivores like bristle worms, mantis shrimps.

IMO (naturally), vigorous, efficient protein skimming. There are advocates of no-skimming or intermittent skimming with SPS', and they are correct in asserting that skimming removes food/chemicals, bio-useful minerals and trace elements, but these essential materials should be replaced through feeding (see below), water changes, and live rock (and possibly sand) use.

Acclimation:

Transport: For short hauls (under an hour) simple "water bagging" in double fish bags will do. Longer transit times call for upside down "Styrofoam hanging" to "moist bagging" techniques.

On Arrival: Some aquarist/writers advocate a drip method of easing specimens entry to new water chemistry, followed by gentle wafting of extruded mucus. Many commercial concerns utilize separate intermediary containers with main system water for this purpose, eliminating "mixed" water and exudate altogether. This is my favored approach. In commercial shipments and following wild collection, most businesses process their stony corals through a treatment bathe protocol. Some use pH adjusted freshwater, iodine in various formats, and/or sugars. This step should be unnecessary for short transit times from penultimate dealers to end users. Adequate quarantine almost guarantees elimination of pests, parasites and infectious disease agents.

Placement: Should be made in a less lighted, but well-circulated part of your system initially, with adequate spacing from other stinging celled organisms and their sweeper tentacles.

Foods/Feeding:

This is a semi-controversial area. Many aquarists and commercial culturists abstain from offering purposeful foods, having their Acroporids rely solely on apparent photosynthesis... and nutrients that come from other biological activity in the system. In our culture facility (WWM) we offer a nutrient "bath" to our hermatypic SPS' on a daily basis. We observe faster, thicker growth, with more color and hardiness from this practice. Our "food/feeding" consists of a pureed squirt of a blend of unicellular algae, zooplankters, suspended particles (animal based flake foods), and dissolved organics.

Regarding the use/misuse of "supplements". Notwithstanding my jealousy of associates in pet industries vast wealth from such sales, I/we don't use "additives". Water changes, feedings and the use of carbon dioxide calcium reactors grant us 400-500ppm of calcium plus high alkalinity & other factors necessary for biomineralization. If you feel you must "supplement" to get sufficient strontium, calcium, iodine, iron, boron... into your livestock, please be careful... know what you're doing, utilize test kits, and as your best saving grace, utilize regular water changes as a dilution solution.

Other General Health Notes:

Vitamin preparations and amino acid complexes are a good idea, Proline and glutathione in particular have been found to be rate-limiting in culture. These are best applied in advance to the food being "sprayed", not to the water directly.

B) Water changes, with pre-mixed (a week or more) synthetic, or real seawater... have I mentioned them enough?

C) Treatments, no! Do not expose your corals to metal or dye solutions... which brings us to:

Quarantine. Don't fool yourself into thinking that having an "extra" set-up for holding new arrivals is an unnecessary extravagance. The gear and procedure is far cheaper than losing your whole display to a careless introduction of stressed and/or diseased livestock. Bleaching is generally the result of sudden or large changes in temperature and/or lighting. Be on guard against such swings through control and gradual lamp replacement strategies.

Zanclea Hydroid on Acropora hyacinthus. Red Sea (Open the linked page size pic to see more clearly)

Acropora Eating Flatworm (AEFW), on.... Acropora. Red Sea.

Reproduction/Culture:

Acroporids and other SPS species make up the spectacular seasonal mass spawners we've all read about and seen on "nature" shows on television. However this is only the beginning of their reproductive and regenerative repertoire. Most folks capitalize on the groups "divide and conquer" strategy of fragmentation to make new colonies. Small pieces of healthy Acroporids can be broken off and attached to real or faux substrate and under propitious circumstances give rise to genetically identical "frags".

Frag momma frag, what'cha gonna do?

A Note Re Conservation:

It's not lost on me that in Dante's Inferno, the lowest ring of Hell was reserved for the worst sinners: hypocrites. After many years of working in the ornamental aquatics trade, as well as writing for the hobby and business interests of the field as well as the scuba-sport 'zines, is it right to actually endorse the use of these organisms? In my opinion, a qualified yes. Granted the stony corals that are collected must be of appropriately gathered (not all from every environment), carefully handled and placed in favorable settings. But beyond these stipulations, that the consumer, you and I as aquarists, do our best to act out of understanding and do our best to appreciate, and in the case of easily culturable forms, spread our knowledge and pieces of our specimens to other hobbyists.

I entreat you, don't get involved with stony corals nonchalantly. Reef keeping is an expensive, time-consuming passion. If you're new to the reef scene, do start with non-mineralizing stinging celled animals that have faster replacement rates, graduating to LPS and SPS corals with mastery of your aquaristic skills. And do your best to purchase cultured specimens and in turn provide them to others yourself. Captive produced corals not only conserve wild stocks, they are better choices: pre-adapted to aquarium conditions, relatively free of parasitic, infectious and collateral pest organisms.

Conclusion:

The family Acroporidae comprises many species; some stellar and a few aquarium disappointments. As with all SPS they require consistent, metabolite-free water and intensely lit, well-circulated conditions. Given their capacity for asexual culture, diversity, abundance and beauty, this group will remain a prominent part of advanced reef aquarists dreams and aquaculture efforts.

Bibliography/Further Reading:

Coral Search

Blackburn, Wayne. 1988. Corals in the reef tank. FAMA 12/88.

Borneman, Eric & Jonathan Lowrie. 1998. Rapid tissue necrosis- a new understanding. FAMA 6/98.

Branikowski, Edward J. 1993. The collection, transportation and maintenance of living corals. SeaScope v.10, Spring and Summer 93.

Bruckner, Andrew W. & Robin J. 1998. Emerging infections on the reefs. Natural History 1/98.

Colin, C.L. & C. Arneson. 1995. Tropical Pacific Invertebrates. Coral Reef Press, Beverly Hills, CA. Pp. 296.

Delbeek, J. Charles. 1990. Reef aquariums: coral compatibility. As a reef tank becomes established, corals will grow and require more space. AFM 10/90.

Denison, W.C. 1988. Effect of water motion on coral photosynthesis and calcification. J. Exp. Mar. Biol. Ecol. 115:67-77.

Fossa, Svein A. & Alf Jacob Nilsen. 1993. Stony corals. Can they grow in a closed reef aquarium? FAMA 9,10,11/93.

Fossa, Svein A. & Alf Jacob Nilsen. 1996. The Modern Coral Reef Aquarium, v.1. Birgit Schmettkamp Verlag, Bergheim, Germany. Pp. 367.

Fossa, Svein A. & Alf Jacob Nilson. 1998. The Modern Coral Reef Aquarium, v.2. Birgit Schmettkamp Verlag, Bornheim, Germany. Pp. 479.

Frissell, Christopher A. 1981. Living coral in the marine aquarium. FAMA 2/81.

Gutierrez, Santiago. 1990. From a reef's point of view: Acropora cervicornis. FAMA 11/90.

Janes, Michael P. 1999. Buyer's guide to corals. FAMA 6,7/99.

Klostermann, A.F. 1993. Coral growth in captivity. FAMA 5/93.

Knop, Daniel. 1998. Artificial propagation of corals- the stony corals. Aquarium Frontiers On-Line 2/98.

Muscatine, L. 1973. Nutrition of coral. In Biology and Geology of Coral Reefs, v. II Biology. Jones, O.A. and R. Endean, Ed.s Academic Press, NY pp. 77-115.

Paletta, Michael. 1992. Propagating corals in the mini-reef. SeaScope v. 9, Winter 92.

Paletta, Michael. 1994. Selecting healthy corals. Making the right choices for your reef tank. AFM 7/94.

Paletta, Michael. 1995. The care and maintenance of corals. AFM 2,3/95.

Paletta, Michael. 1996. Dangerous neighbors. Placement of corals in the reef tank. AFM 8/96.

Paletta, Michael. 1997. Small-polyped stony coral blight; something has been going wrong in reef tanks. AFM 5/97.

Paletta, Michael 1997. Coral update. Small-polyped stony corals revisited. AFM 9/97.

Parks, Noreen. 1993. Immortal corals. Reef builders use incest to slow evolution. Sea Frontiers 1,2/93.

Perrine, Doug. 1994. Sex and the single scleractinian. Sport Diver 5/6, 94.

Riddle, Dana. 1994. Coral nutrition. Notes, thoughts, and theories. FAMA 4-8/94.

Riddle, Dana. 1995. Life, light and lipids; the importance of lipid in coral diets. 6,7/95.

Riddle, Dana. 1999. Coral killer? The case against two species of red algae. FAMA 2/99.

Siegel, Terry. 1997. Question from a reader (re: SPS selection). Aquarium Frontiers On-Line 10/97.

Siegel, Terry. 1998. A coral for all seasons- Montipora. Aquarium Frontiers On-Line 8/98.

Stepanov, Dmitry. 1994. Coral feeding in nature and in the aquarium. FAMA 1/94.

Stromgren, T. 1987. The effect of light on the growth rate of intertidal Acropora pulchra from Phuket, Thailand, latitude 8 degrees North. Coral Reefs 6:43-47.

Teh, Y.F. 1974. Keeping live coral. Marine Aquarist 5(1):74.

Vargas, Tony. 1995. Acropora: the reef builder. FAMA 5/95.

Vargas, Tony. 1997. One acropora becomes three. FAMA 5/97.

Vargas, Tony. 1997. Feature coral: Montipora. FAMA 8/97.

Veron, J.E.N. 1986. Corals of Australia and the Indo-Pacific. Angus and Robertson, Publishers, North Ryde, NSW, Australia. Pp. 644.

To: Part 2, Part 1

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