News / Species Spotlight / Montipora Corals (11/26/15)

Montipora Corals

by Charles J. Hanley III



Scientific Name: Montipora digitata, M. foliosa, M. danae, M. capricornis, M. samarensis, M. spumosa, and many others

Common Name(s): Velvet Coral, Vase Coral, Rainbow Coral, Superman Coral, Poker Star Coral, Velvet Stone Coral

Taxonomy:

Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Acroporidae
Genus: Montipora

Description:

Small polyped scleractinian, or SPS, corals are pretty much the zenith of reef-keeping. SPS corals are some of the most electrifying, hard to care for, and misunderstood corals in the aquarium trade. Fortunately, the cumulative knowledge of tens of thousands of reef-keepers, going back decades, has made growing and propagating SPS corals achievable for even the novice. Of all SPS species available, those of the Genera Acropora and Montipora are the most popular and readily available. The focus of this Species Spotlight article is the Genus Montipora.

Montipora corals exemplify the best in coral variation and adaptability. In fact, Montipora spp. come in so shapes, colors, and sizes that experts and scientists find it difficult to differentiate between many individuals of the 87 recognized species. Some experts even claim that it is safe to assume that a given species name is incorrect, no matter how it is presented. Nonetheless, in the Aquarium Care section, I will cover a few important generalized facts which will help to ensure the survival of your Montipora colony, regardless of its true identity.

As previously mentioned, all Montipora spp. are SPS corals which form medium to large colonies, depending on the species and location. They are zooxanthellate and hermatypic, and in some cases can form massive reef structures made entirely of conspecifics. In other words, whole reefs may essentially be a single colony. Their morphologies are highly variable, and include encrusting, digitate (finger-like), columnar, plate-like, and foliose (flower-petal like) structures, as well as aborescent (tree-like) and anatomosed (fused) branches. Coloration ranges from brown, green, and purple to red, blue, orange, pink, and yellow. The tentacles may be the same color as the connective tissue layer, the coenosarc, or they may be a brightly contrasting color. A great example of this contrast can be seen in the aptly named Superman Montipora, which often sports brilliant red tentacles set against a striking royal blue base.

Natural Habitat and Ecology:

Though found in all tropical seas, Montipora specimens are most common in the central and Indo-Pacific regions, especially those significant in the aquarium trade. Their variable body shapes, as well as the ability to house several different photosynthetic symbionts (e.g. algae, dinoflagellates, and cyanobacteria,), provide them flexible solar requirements. That is, some species are able to adapt to both shallow waters with bright sunlight as well as deeper, more dimly lit areas. Consequently, Montipora corals are found in every zone on a coral reef. Lagoonal species are robust to changing water qualities, while those near the reef crest are able to withstand intense solar bombardment. Further out, colonies on the outer reef slopes are able to form delicate branches or plates, with complex contours designed to maximize the collection of dwindling sunlight.

Reproduction, like most corals, is both sexual and asexual. Montipora species are known to participate in precisely timed mass spawning events. They are also capable of growing new colonies from broken pieces, whenever the fragments fall into suitable locations. Perhaps the most important method of reproduction, however, is simply the outward growth of existing colonies. As the skeleton (theca) grows upward or outward, new corallites develop, along with the new polyp (which is, of course, a new animal). Under superior conditions, this growth can be quite rapid. Many anecdotal aquarium stories recount a very small frag growing to undesired proportions within a year or two of purchase.

Aquarium Care:

Since SPS corals are generally considered to be suitable for advanced aquarists only, Montipora species are often underrated for their hardiness and adaptability. While I would not recommend them to a true beginner, I do think that this genera is appropriate for higher-level novices who have shown a deft touch for coral care. My criteria is not usually dependant upon overall knowledge of the field as much as the ability to learn new information and the willingness to provide diligent husbandry. So much success in this hobby is attributable to having the discipline to attend to your tank daily. Really, you can know all there is to know about coral, but if you do not take the 10 to 15 minutes a day to maintain your system, what good is all that knowledge doing you? Conversely, you may not understand why magnesium affects calcium availability, but you can certainly keep magnesium at recommend levels and just not have to worry about it!

From research and my own experiences, it seems that there exist two major fallacies which cause SPS corals to die in captivity. The first is that they must be placed directly beneath intense metal halide lighting. While it is certainly true that some species of Acropora and Montipora corals need this type of lighting regime, or at least thrive better under it, to suggest that all do is a huge misrepresentation of the facts. Clearly, not all species hail from such shallow, brightly lit waters. Deeper water species may quickly become bleached when subjected to too much light, although Montipora species are much less susceptible to this phenomenon. Further, some individuals may survive well under intense lights, but exhibit their best colors under more moderate conditions. Sometime the reverse is true. The simple fact is that Montipora corals are being successfully kept under metal halides, T5 fluorescents, LEDs, and even Power Compact fluorescents! Each specimen should be considered individually, and you should not be afraid to change its location if the polyps do not extend properly. Of course, full polyp extension should happen only at night, but all of the polyps will extend partially if the colony likes the lighting. When the light is too heavy, the polyps will retract completely and the coral will eventually bleach. If the colony is not lit well enough, some polyps will extend too fully and the colony will tend to turn brown. The best course of action is to assume that the frag needs moderate lighting, and then adjust based on the way the polyps react.

The second misinformed idea is that SPS corals just need very clean water with high calcium levels. While neither fact is actually untrue, they do not tell the whole truth. For example, Montipora animals can be found in lagoons, where the water can become turbid and nutrient laden. The fact that they are hardy enough to survive the rigors of lagoonal environments lends to their hardiness in an aquarium. I do not recommend exposing them to dirty water, but a small increase in nitrates should not hurt them either. Similarly, while calcium should be maintained between 400 to 450 mg/L, keeping proper pH and magnesium levels is just as essential for calcium deposition. If either is too low, calcium becomes less available for the coral to absorb and use in skeletal creation. Magnesium is best maintained around 1300 mg/L, while pH should range between 8.1 and 8.4. Equally important is alkalinity, which must be at least 9.1 dKH to maximize growth potential. Also consider keeping strontium levels between 8.0 and 10.0 mg/L. Strontium is a micronutrient which is incorporated into coral skeletons, but care should be taken not overdose the tank to prevent a toxic buildup of the chemical. As always, I recommend using a high quality micronutrient supplement, coupled with regular parameter testing. In fact, you should never supplement chemical constituents without a consistent testing regime.

The final requirement for Montipora success is water flow. These corals must be maintained in a system with adequate water movement. They will do poorly in sluggish water and will likely succumb to algal growth when detritus is not scoured from their surfaces. On the other hand, the delicate polyps can tear or fail to open altogether if the water flow is too hard. The best indicator for proper water flow is a gentle waving of the extended polyps. The correct water flow will keep the oral surfaces clean, and help to bring micro-plankton to the coral mouths. Micro-plankton should be supplemented at least once weekly, preferably after the tank lights have turned off.

The last piece of important information regarding Montipora corals concerns the parasitic nudibranch which feeds upon their tissues (see our article 'The Montipora Eating Nudibranch' for more info). The nudibranchs can be difficult to see, especially since they tend to feed on the underside first. They are also well-camouflaged against the coral surface. The development of discolored areas may be an indicator that the smallish nudibranchs are present. Several treatment options exist, including iodine and Lugols dips. Some aquarists have even taken to mechanically removing the pests with tweezers. For natural methods, turn to one or more of the following fish species:

  • Red Sea Butterfly fish (
  • Thread Fin Butterfly fish (
  • Thalassoma
  • Coris
Quick Notes:

  • Adjust lighting regime based on polyp extension and coloration.
  • Control pH, calcium hardness, alkalinity, magnesium, and strontium levels.
  • Maintain moderate water flow.
  • Quarantine new animals and perform prophylactic treatment for pests.
  • Supplement live algae and/or microplankton once weekly.


Works Cited:

Anonymous. Montipora. ITIS Report. 2010. URL: http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=all&search_value=Montipora&search_kingdom=every&search_span=exactly_for&categories=All&source=html&search_credRating=All

Brightwell, C.R. Marine Chemistry, A Complete Guide to Water Chemistry in Marine Aquariums. T.F.H. Publications: Neptune City. 2007.

Goldstein, Robert J. Marine Reef Aquarium Handbook. Barrons: Hauppauge. 1997.

Montipora. Wikipedia entry. 2010. URL: http://en.wikipedia.org/wiki/Montipora

Perun, Blane. Montipora Nudibranch. Web entry: TheSea.org. URL: http://thesea.org/montipora/Montipora_Nudibranch.htm

Perun, Blane. Superman Montipora. Web entry: TheSea.org. URL: http://thesea.org/montipora/Superman_Montipora.htm

Perun, Blane. Montipora foliosa. Web entry: TheSea.org. URL: http://thesea.org/montipora/Montipora_Foliosa.htm

Perun, Blane. Red Montipora. Web entry: TheSea.org. URL: http://thesea.org/montipora/Red_Montipora.htm

Riddle, Dana. Montipora digitata: A Stony Coral for All Hobbyists. Advanced Aquarist Online Magazine. 2008. URL: http://www.advancedaquarist.com/2008/1/aafeature2

Shimek, Ronald L. Marine Invertebrates, 500+ Essential-to-Know Aquarium Species. T.F.H. Publications: Neptune City. 2004.

Tullock, John H. Natural Reef Aquariums, Simplified Approaches to Creating Living Saltwater Microcosms. T.F.H. Publications: Neptune City. 2001.