Goniopora

Goniopora is a genus of stony coral that extends hundreds of polyps on long stalks from its skeleton during the day. At the tip of each polyp is a small flower made up of about 24 short tentacles; when the colony is fully open it looks like a bouquet of flowers placed in a pot. The polyps of the similar-looking Alveopora have only 12 tentacles; this number is the easiest way to tell them apart.

For many years Goniopora was known as the coral that "looks healthy for months and then wastes away within a few weeks"; it is not suitable for beginners. In recent years, success rates have risen thanks to aquacultured or maricultured colonies and a better understanding of its feeding needs. Identification to species level is difficult in the store, so this page covers the genus as a whole. Its trade is subject to CITES Appendix II; choose a captive-grown colony instead of a wild-collected one.

• Red Goniopora: The form with red-burgundy polyps, the most sought-after in the hobby.
• Green Goniopora: The common form with green polyps and pale tips.
• Two-tone forms: Colonies in which the stalk and the flower part are different colors.

It lives in the Indo-Pacific, especially in turbid waters and on sheltered reefs. Some species form large single-species stands; Goniopora stokesi, on the other hand, mostly sits free on sandy bottoms. Living in turbid water shows that it gets a significant part of its nutrition from fine particles in the water.

• Light: Moderate, about 100–250 PAR. Change the lighting gradually over weeks.
• Flow: Moderate, variable and surging. The polyps should not constantly lie in one direction; with very weak flow, detritus settles on the polyps.
• Placement: The middle or lower zone of the rockwork; free-living colonies such as G. stokesi go on the sand.
• Water parameters: Salinity 1.024–1.026, KH 7–10 dKH, calcium 400–450 mg/L, magnesium 1250–1350 mg/L. It is very sensitive to stability. Nutrients should not drop to zero: nitrate around 5–10 mg/L and phosphate around 0.05–0.1 mg/L are more suitable. It should go into a mature aquarium that has been running for at least a few months.

It is photosynthetic, but its long-term survival appears to depend on supplemental feeding. It needs fine foods that the small polyps can catch: several times a week, offer phytoplankton, rotifers, copepods or powdered coral food near the colony with the flow turned down slightly. The polyps cannot catch large foods.

Its long polyps sting and can burn surrounding corals; it is also easily affected by the chemicals of soft corals. Leave at least 10–15 cm of space between it and its neighbors and use activated carbon. Do not place it within reach of aggressive species such as Euphyllia and Galaxea.

Clownfish may host in Goniopora, and constant contact wears down the polyps. Dwarf angelfish and butterflyfish may pick at the polyps.

Healthy, growing colonies can be propagated by cutting with a diamond-blade saw; the cut should be made when the polyps are retracted. Goniopora stokesi also forms small satellite colonies within the tissue of the mother colony; these can eventually break off and live separately.

• Polyps not opening or getting shorter: May be due to starvation, a change in flow, KH swings or the chemical effect of a neighboring coral.
• Slow decline: A colony that has looked healthy for months may suddenly start losing tissue; this is mostly associated with insufficient feeding and overly clean water.
• Brown jelly and tissue recession: Progresses quickly; the affected part should be cut off and removed.