Montipora undata

Montipora undata is a Montipora that spreads over rock like a crust at first, puts out fairly thick plates from its edges as the colony grows, and sometimes also forms small knobs growing upward. Its polyps are very small and sit scattered between fine ridges on the surface. The identity of the corals sold as "undata" in the hobby is disputed; some are thought to be other Montipora species, but their care is the same. Trade in stony corals is subject to CITES Appendix II; choose an aquacultured frag.

• Purple Undata: An aquacultured clone known for its thick, deep purple plates and a light purple growth edge.

• Light: Moderate to high light; roughly 150–300 PAR. Under strong light the purple color may shift toward blue; acclimate a new piece gradually.
• Flow: Moderate, random flow. Because the plates act like sails, attach the colony securely to the rock and avoid very harsh flow.
• Placement: A surface in the middle part of the rockwork where it can spread and open out its plates.
• 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.

It is photosynthetic; light and zooxanthellae algae provide most of its energy. No extra feeding is needed; nutrients dropping completely to zero fade its color.

It is a peaceful coral, but its spreading base and opening plates shade its neighbors and grow toward them; leave 10 cm of space. Long-tentacled LPS sting it. The Montipora-eating nudibranch (Phestilla subodiosa) can hide on the underside and along the edges of the plates; put new pieces through a coral dip and inspect them.