Cyphastrea microphthalma

Cyphastrea microphthalma is a stony coral that grows over rock as a thin crust or a low mound. Its surface is covered with small, round, slightly raised corallites with gaps between them; the species name comes from these "small eyes". Where light is lower it spreads as thin plates. In the hobby, forms whose body and polyps are different colors are popular.

The Cyphastrea sold in the trade are often identified only to genus level; it is usually not certain which species the colorful forms belong to. Since the common species of this genus in the hobby all have the same care, the information on this page applies to them as well.

With its hardiness and low light needs, it is one of the best species for getting started with stony corals. Trade in stony corals is subject to CITES Appendix II; most Cyphastrea in the hobby are already aquacultured frags.

• Meteor Shower: Orange-red polyps on a turquoise-blue base. One of the first named Cyphastrea to enter the hobby; it is not certain which species it belongs to.
• Other color forms: There are many forms in golden yellow, green and brown tones, sold under names given by vendors.

It is common across most reef areas from the Red Sea to the Indo-Pacific; it is found on reef slopes, in lagoons and on coastal reefs where the water can become turbid. Taking a mound shape when light is plentiful and a thin plate shape when it is scarce makes it adaptable to different environments.

• Light: Low to moderate light; roughly 75–200 PAR. Too much light bleaches the base and dulls the polyp colors. Keep a new piece under low light for the first two weeks.
• Flow: Moderate, indirect flow; enough that no detritus settles on the surface. Harsh, direct flow strips the tissue.
• Placement: The middle or lower part of the rockwork. Because it spreads, placing it on a separate rock (an island) or on a rock near the back wall makes it easier to control.
• Water parameters: Salinity 1.025–1.026, KH 7–9.5 dKH, calcium 400–450 mg/L, magnesium 1250–1400 mg/L. It is far more tolerant of nitrate and phosphate than Acropora; it does well at nitrate 2–15 mg/L and phosphate 0.03–0.1 mg/L.

It gets most of its nutrition from the zooxanthellae algae in its tissue and can live on light alone. Its polyps open after the lights go off; fine powdered food or rotifers given at that time one to three times a week can speed up growth.

At night it can extend short sweeper tentacles and sting corals that come close; their reach is short, but leave 5–8 cm of space. Its main impact is spreading: over time it advances across the rock and can overgrow the base of low-growing animals such as zoanthids or slow-growing corals. Strong LPS such as Torch, Galaxea and Favia, on the other hand, sting it.

Dwarf angelfish may pick at the polyps. No common pest specific to this genus is known in the aquarium.

The encrusting colony is broken into pieces together with the rock beneath it using coral cutters, a chisel or a small saw, and the pieces are glued onto frag plugs. Another method is to place a frag plug so that it touches the edge of the colony and wait for it to spread over. Because it grows slowly, a frag only covers its plug within a few months.

• Bleaching of the base, color fading: There is too much light; move the coral lower.
• Tissue loss from the edges: Detritus buildup, KH swings or stinging by a neighboring coral. Review the flow and spacing.
• Polyps not opening: Normal for a few days after a new placement; if they do not open at night either, the flow may be too harsh.