Montipora setosa

Montipora setosa is a Montipora that grows short, irregular branches, knobs and small columns upward from a base covering the rock. Because its surface is covered with fine projections, up close it looks rough and velvety. Its best-known forms in the hobby are vivid orange, red and pink; green and cream colonies also exist. The same piece can take on a more encrusting or a more branching shape depending on light and flow.

It has the forgiving nature of the genus Montipora: it is not as sensitive as Acropora, but it needs good light, steady flow and stable water chemistry to keep its colors. Because the colorful forms quickly turn brown in poor conditions, its difficulty is rated "moderate".

International trade in stony corals is subject to CITES Appendix II. Aquacultured frags and farmed colonies are easy to find; choose these.

It lives in the western Indo-Pacific, on shallow reef slopes with plenty of light and steady flow. Here its colonies, spreading tightly over the rock, withstand wave action. The short, stubby branches are also an adaptation to this turbulent environment.

• Light: Moderate light; roughly 150–250 PAR. It can be acclimated slowly to stronger light, but a sudden increase bleaches the tissue.
• Flow: Moderate to strong, indirect flow that changes direction. Detritus should not build up in the hollows between the knobs.
• Placement: The middle part of the rockwork; choose a flat surface where its base can spread.
• 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. When nitrate and phosphate rise, the orange and red tones are the first colors to go.

It gets most of its nutrition from the zooxanthellae algae in its tissue. Extra feeding is not required; fine particles left over from fish food and dissolved nutrients in the water are enough. If powdered coral food or phytoplankton is given, give small amounts and monitor nutrients.

It is a peaceful coral and does not sting its neighbors. Its encrusting base gradually spreads over the rock and can reach the bases of neighboring corals; leave at least 8–10 cm of space. Euphyllia, Galaxea and other LPS that extend sweeper tentacles sting it.

Dwarf angelfish and butterflyfish may pick at the polyps. The Montipora-eating nudibranch (Phestilla subodiosa) attacks this species too; the recesses between the knobs are good hiding places.

Branch and knob tips are cut with coral cutters and attached to a frag plug with gel glue. Pieces of the encrusting base can also be propagated by breaking them off together with a small stone. Frags spread onto the plug within a few weeks and put out new knobs.

• Color loss: The orange form turning brown points to low light or high nutrients; whitening points to a sudden increase in light.
• Tissue receding at the base (STN): Detritus buildup, algae and KH swings are the main causes. Increase flow and stabilize the water parameters.
• Bite marks: Look for nudibranchs and their eggs; put new pieces through a coral dip and observe them for a few weeks.
• Vermetid snails: Their mucus nets irritate the tissue; seal their tubes.