MARINE INVERT
of the Month
Bob Goemans photograph by the author
Parazoanthus gracilis
Common Name(s):
Yellow polyps/colonial
yellow polyps
Phylum: Cnidaria
Class: Anthozoa
Order: Zoanthiniaria
Family: Parazoanthidae
Range: Tropical Western
Pacific Ocean
Natural Environment: Inhabits
shallow reef environments and is
usually found encrusting rock and other
matter such as sponges, gorgonians, and
hydroids in areas receiving moderate
light and moderate water movement.
Forms encrusting anemone-like yellow
polyps that are connected at the base via
small canals, and forms groups of polyps that can attain a height of about 3 inches ( 8 cm). Receives the majority
of its nutrition by capturing zooplankton.
Captive Care: This is a beautiful and somewhat hardy animal if fed various meaty foodstuffs, e.g., cyclops,
enriched brine shrimp (live or defrosted), or mysis. Will even accept some flake foods! It should be placed in
moderately lit areas having moderate water flow. Caution is required if placed near other corals and the specimen
is fed, as it can rapidly spread onto nearby corals and harm them. Tends to dissipate if hair algae begins to grow
on the same piece of substrate that it’s colonizing.
This is a commonly collected species and is almost always available in the trade.
Water Quality Requirements: Alkalinity 3. 5 meq/l (I’ve personally found it to do better at 4.0 meq/l), pH 8. 1
to 8. 2, specific gravity 1.022 to 1.026, and a temperature range of 74° to 83°F ( 23° to 28°C).
Notes: Some are of the opinion that this species is wrongly identified, and may possibly belong
in the family Zoanthidae, genus Acrozoanthus. And there are also questions as to whether or
not this particular species contains zooxanthellae. My experience has shown that it’s not capable
of photosynthesizing, as I’ve always seen a reduction in polyp size and numbers if not fed. It
just seems to waste away and get smaller if not supplied proper nutrition. Until there is more
information on species identification, I’ll continue to classify it as mentioned above. There is also
a similar Atlantic species, identified as Parazoanthus axinellae.
