Pavona decussata

Pavona decussata is a stony coral that forms fairly thick upright fronds and radiating ridges on a semicircular base. The fronds are between a few millimeters and one centimeter thick and carry small corallites on both faces. Its color can be greenish, brown, orange or creamy yellow; the growth edges are usually lighter. Vendors often write the name as "decussatus".

It has thicker, sturdier fronds than Pavona cactus, so it breaks less often during maintenance. It does well under moderate light and moderate flow and is far more forgiving than Acropora. A mature aquarium and stable KH are still necessary.

Trade in stony corals is subject to CITES Appendix II. Aquacultured frags are easy to find; choose these instead of a wild-collected colony.

It ranges from East Africa and the Red Sea to Japan, the Philippines and eastern Australia. It is a fairly common species, found especially on gently sloping reef surfaces down to a depth of about 15 m. This depth range explains its preference for moderate light.

• Light: Moderate light; roughly 100–250 PAR. A new piece should be kept under lower light for the first two weeks.
• Flow: Moderate flow that changes direction. Detritus should not build up in the recesses between the fronds.
• Placement: A horizontal or gently sloping surface in the middle part of the rockwork. The colony expands outward.
• Water parameters: Salinity 1.025–1.026, KH 7–9 dKH, calcium 400–450 mg/L, magnesium 1250–1400 mg/L, nitrate 2–10 mg/L, phosphate 0.02–0.08 mg/L. Sudden KH swings cause tissue loss along the frond edges.

It is photosynthetic; light and the zooxanthellae algae in its tissue cover most of its energy. Its polyps are small, so it cannot take large foods. Phytoplankton or very fine powdered food given now and then makes a limited contribution; it is not essential.

Pavona species can develop sweeper tentacles and sting the corals they touch. Leave at least 10–15 cm between it and neighboring corals. Euphyllia, Galaxea and other long-tentacled LPS, on the other hand, sting it.

Dwarf angelfish and butterflyfish may pick at the polyps. No common aquarium pest specific to this species is known; still, put new pieces through a coral dip and observe them for a few weeks.

One of the fronds is cut near its base with coral cutters or a small saw and attached to a frag plug with gel glue. Because the fronds are thick, cutting is easier than with P. cactus. Cleaning the cut surfaces with an iodine coral dip reduces the risk of infection. Within a few weeks the frag spreads onto the plug and puts out new fronds.

• Tissue loss from the edges: KH and temperature swings or detritus buildup. Stabilize the water parameters first.
• Bleaching: A sudden or excessive increase in light; move the coral lower and acclimate it slowly.
• Browning: Lack of light or high nutrients.
• Sting marks on a neighboring coral: Increase the distance; one of the two corals at the point of contact will keep getting damaged.