Tree Coral

Care

Although arguably some of the most beautiful and colourful corals in the world, members of the Dendronephthya and Scleronephthya genera can, unfortunately, be very difficult to maintain long-term in the home aquarium. The colonies can reach a considerable size in the wild, and when fully expanded, have a broccoli-like appearance, but in much gaudier colours such as vivid reds, oranges, yellows, purples, and pinks. The stalks and branches display clusters of polyps at the terminal ends; these are all non-retractable and autozooid (feeding polyps). Tree Corals in the Dendronephthya genus all possess prolific sclerites - these are needle-like and often brightly coloured, and are easily visible through the translucent tissue of a fully expanded specimen. These long, slender, pointed sclerites, which give the corals some degree of support, are also thought to facilitate gas and water exchange. Scleronephthya spp. tend to have slightly shorter stalks, are less highly branched, and do not boast such a multitude of visible sclerites. Nevertheless, their care requirements are identical and equally as challenging. The natural habitat of Tree Corals is primarily dimly lit regions underneath ledges, overhangs, and inside caves; yet, several species are also found on reef slopes under full sunlight. However, the one thing all members of these two genera have in common is that they are all found in areas of constant current that delivers an ongoing stream of planktonic food items. Observations have shown that they are pretty much unknown from regions with a water flow of less than 5cm/sec (2"/sec) and also tolerate much faster currents than those of other corals. A study by Dahan & Benayahu in 1997 on D. hemprichii found that polyp expansion only occurred between 3cm/sec (1.2"/sec) and 25cm/sec (9.8"/sec). So the correct strength of water flow is paramount for their ability to feed and continued wellbeing. Much of the available information regarding diet is educated hypothesis. It is assumed that these voracious feeders directly absorb nutrients from the surrounding water with the polyps also feeding constantly on phytoplankton and zooplankton. However, at least one species is known to produce sweeper tentacles, which throws into question the assumption that all feed solely on planktonic food items. As they lack zooxanthellae, Tree Corals need to be fed heavily in the home aquarium with phytoplankton and zooplankton. This almost needs to be delivered via a constant drip into the aquarium. However, with such constant, heavy feedings, it can be very challenging to maintain water quality within the confines of a typical reef aquarium. Additionally, it is noted that these corals tend to fare best in aquaria with well-established sand beds that accommodate large volumes of tiny invertebrate larvae. To summarise: these exquisite corals are very difficult to provide for in the home aquarium, even when the healthiest of specimens are obtained, and they should only be purchased if the aquarist is able to provide them with the exceptional, specialist care that they demand. More often than not, aquatic stores do not directly order these species from their suppliers, but they turn up unexpectedly from time to time in shipments of assorted corals. Be aware that Tree Corals contain a fairly high concentration of toxic compounds, so handle with caution; however, this does not stop a number of predatory snails. May also be seen on sale as Carnation Coral or Cauliflower Coral. Advanced aquarists only.

Feeding

Very difficult. Tree Corals require constant, heavy feedings of phytoplankton and zooplankton, delivered via drip into appropriate currents. Such continual provision of nutrients can have a detrimental effect on water quality and aquarium inhabitants. It is extremely problematic to get the balance just right. Also requires an aquarium with mature sand bed to provide a constant supply of small invertebrate larvae.

Propagation

In the wild, Tree Corals reproduce via several methods: asexually by dropping branchlets, through longitudinal fission, and by budding. Sexual maturity is reached early in Tree Corals - less than a year for the male colonies and less than 1.5 years for female colonies.