Stylophora pistillata

Stylophora pistillata is a stony coral that forms small, rounded bushes of short, fairly thick branches. The branch tips are not pointed but rounded and knob-like. The upper edge of the corallites projects like a hood, which is where the English name "hood coral" comes from. Because its polyps can also open during the day, the colony looks fuzzy. It has pink, purple, green and cream forms.

It is one of the most studied species in coral biology; Red Sea colonies have been researched for many years. In the aquarium it is often recommended for moving into SPS because of its fast growth, easy propagation and relatively wide tolerance. Still, it needs a mature aquarium and stable water parameters.

Trade in stony corals is subject to CITES Appendix II. Most forms available in the trade are aquacultured frags; choose these.

• Milka (purple Stylophora): The form known for its lavender-purple polyps and white growth tips. It is reported to have been collected in the Red Sea and spread into the European hobby via the Monaco Aquarium; it takes its name from its color, which resembles a purple chocolate wrapper.
• Pink and green forms: The colors found most often in the hobby.

It is common on shallow reefs and in lagoons from the Red Sea to the Indian Ocean and the Western Pacific. In upper zones with strong light and steady flow it forms small, densely branched colonies; in calmer places, more open-branched ones.

• Light: Moderate to high light; roughly 150–300 PAR. Pink and purple tones become pronounced under blue-heavy light; under very strong light the pink form turns almost white, and under low light it browns. A new frag should be acclimated to the light over two to three weeks.
• Flow: Moderate to strong, random flow; no detritus should remain between the dense branches. Avoid flow that constantly hits a single spot.
• Placement: The upper half of the rockwork, with 10 cm of space around it.
• Water parameters: Salinity 1.025–1.026, temperature 25–26.5°C. 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. It is more tolerant than Acropora, but a sudden KH change causes tissue loss from the base.

It gets most of its nutrition from zooxanthellae algae. Fine powdered food given once or twice a week, with the pumps turned off for 10–15 minutes, can support growth and color. Feeding is not required.

Its aggression is low; its short tentacles can only lightly sting a coral they touch directly. It is itself vulnerable to long-tentacled LPS and soft corals; leave 10 cm of space.

Dwarf angelfish and butterflyfish may pick at the polyps. Wild colonies may have guard crabs (Trapezia) between the branches; they are harmless. No common pest specific to this species is known in the aquarium, but like every newly arrived stony coral it should be put through a coral dip.

Branch tips 2–3 cm long are cut and attached to a frag plug with gel glue; they spread onto the plug within a few weeks. The species also reproduces by releasing larvae (planulae); in an aquarium with a mature colony, small Stylophora may appear on the rocks on their own.

• Tissue loss from the base (STN): KH swings, detritus or algae collecting at the base are usually the cause.
• Rapid bleaching: Temperature exceeding 28°C or a sudden increase in light. Keep the temperature stable.
• Browning: Light is too low or nutrients are high.
• Polyps not opening: Normal for a few days after a new placement; if it lasts longer, review the flow and light.