MARINE INVERT
of the Month
Bob Goemans photograph by the author
Pavona cactus
(FORSKÅL 1775)
Common Name(s):
Cactus coral, lettuce
coral, potato chip coral
Phylum: Cnidaria
Class: Anthozoa
Order: Scleractinia
Family: Agariciidae
Range: Indo-West Pacific and
Red Sea, including western,
northern, and eastern coasts of
Australia east to Tahiti, and
north to southern Japan
Natural Environment: This is
a fairly common photosynthetic
stony coral found in lagoons and
on upper-fringing reef slopes that
are somewhat protected from wave
turbulence and where turbid conditions exist. It tends to form massive colonies with frond-like branches that are
upright, thin, and contorted, and with polyps on both sides (bifacial) of the frond-like growths. Its color is generally
brown or greenish brown with white margins.
Captive Care: This is an extremely hardy stony coral; nevertheless, it does need quite good lighting, with metal
halides preferred in the range of 4 to 6 watts per gallon to maintain its growth pattern. If not supplied excellent
lighting intensity, it is capable of photo-adapting to lower levels of light—however, this will influence the physical
structure or appearance of the coral; e.g., its wavy plates will grow wider and more pronounced. Moderate water
movement seems to serve it well, yet an occasional strong wave of water movement helps to keep detritus from
collecting on its surfaces. It’s also a fairly aggressive coral, and capable of developing sweeper tentacles. Therefore,
provide sufficient distance between it and its neighbors in the aquarium.
Even though it is not a common coral in the trade, this species can be considered a good small-polyped stony (SPS)
coral for beginners, as it’s one of the easier-to-maintain photosynthetic stony corals. Even though no direct feeding is
required to keep it healthy, direct feeding can be attempted should increased growth be desired. Although I’ve never
tried hand-feeding this species, zooplankton-type foodstuffs such as rotifers, newly hatched brine shrimp, or cyclops
could be applied over the polyps during daylight hours. If feeding is attempted, water movement should be greatly
reduced while introducing foodstuffs.
Nevertheless, for general health and growth, average water conditions along with good lighting and moderate
water currents will suffice. This coral is easily propagated, with frags generally responding well to placement in
various types of putty media.
Water Quality Requirements: Calcium 380 to 430 ppm, alkalinity 3. 5 meq/l, pH 8. 1 to 8. 2, specific gravity 1.024
to 1.026, Mg approx. 1272 ppm, phosphate < .015 ppm, and a temperature range of 75° to 83°F ( 24 to 28°C).
