Montipora digitata

Montipora digitata is a small-polyp stony coral that grows thick, finger-like branches upward from a base attached to the rock. The branches barely taper toward the tip and end rounded. When the polyps are open the surface looks as if it were covered in short hairs, which is where the English name "velvet" comes from. In the trade, orange, green and purple forms are found most often.

Thanks to its hardiness and fast growth, it is one of the species most often recommended to those who want to start with stony corals (SPS). Being easy does not mean it can be left without care: the aquarium should have been stable for at least a few months, and KH and calcium should be tested regularly.

International trade in stony corals is subject to CITES Appendix II. Because this species is very easy to propagate in aquariums, there is no need for wild-collected colonies; choose a frag or a farmed colony.

It is common in shallow lagoons, on reef flats and on nearshore reefs of the Indo-Pacific. In these areas temperature, light and water clarity can change during the day; the species' tolerance in the aquarium comes from this changeable environment. In the wild, colonies growing side by side form extensive thickets.

• Light: Moderate to high light; roughly 150–300 PAR. Orange and purple forms color up more vividly under strong light. Place a new piece in the middle part of the rockwork first and move it up over a few weeks.
• Flow: Moderate to strong flow that changes direction. Detritus should not build up between the branches, but harsh flow hitting a single spot also strips the tissue.
• Placement: The middle or upper part of the rockwork; allow for the space the branches will grow into upward.
• 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 copes with somewhat elevated nutrients better than Acropora, but its color turns brown.

It is photosynthetic; it gets most of its energy from the zooxanthellae algae in its tissue. It also captures fine particles from the water, so in a regularly fed aquarium with fish no extra coral food is needed. Nutrients dropping to zero fade its color and stop the branch tips from growing.

It is a peaceful coral; it has no stinging or long tentacles. As its branches grow they can touch and shade neighboring corals; leave 8–10 cm of space. LPS with long sweeper tentacles (Euphyllia, Galaxea) harm it.

Dwarf angelfish and some butterflyfish may pick at its tissue. The Montipora-eating nudibranch (Phestilla subodiosa) can hide between the branches and at the base; inspect every newly arrived piece carefully.

It is one of the easiest stony corals to propagate. A 2–4 cm branch tip is cut with coral cutters and attached upright to a frag plug with gel cyanoacrylate glue. The cut tip is covered with tissue within a few days and begins to spread onto the plug within a few weeks. Branch pieces that break off and get wedged between rocks also often become new colonies.

• Tissue loss on inner branches: As the colony becomes denser, the inner branches get no light or flow and their tissue dies. Thin the colony by regularly cutting the outer branches.
• Tissue receding from the base (STN): KH swings, detritus buildup or algae growing around the base are usually the cause. Stabilize the water parameters and clean the base.
• Vermetid snails: The mucus nets they cast irritate Montipora tissue and keep the polyps from opening; seal their tubes in the rock or break them out.
• Bite marks, white patches: Check for nudibranchs and put the coral through a dip.