Toadstool Leather Coral

The toadstool leather coral is the most widely kept member of the genus Sarcophyton in aquariums. On a thick, smooth stalk it carries a wide cap (capitulum) with wavy edges; the top of the cap is covered with long, thin polyps. With its polyps open the colony looks like velvet; when they close, the surface remains perfectly smooth. It has no hard skeleton; small calcareous spicules (sclerites) inside its tissue give the body flexibility and toughness. Its color is cream, beige, light brown or greenish.

Not all colonies sold as "toadstool" in the trade are Sarcophyton glaucum; several very similar species of the genus are sold under the same name, and their care is largely the same. Because it is not a stony coral, it is not covered by CITES; aquacultured pieces produced by cutting are easy to find and acclimate more easily than wild-collected ones.

It lives from the Red Sea to the Western Pacific on shallow reef flats and in lagoons, mostly in places that receive strong sunlight and where waves constantly renew the water. On some reefs it is one of the dominant soft corals covering large areas of the bottom.

• Light: It does well under moderate light (roughly 100–250 PAR); it can be slowly acclimated to stronger light.
• Flow: Moderate, random flow. Flow helps lift off the film on the surface and keeps detritus from building up, but harsh pump flow hitting the cap directly keeps the polyps closed.
• Placement: The middle part of the rockwork or a solid stone. As the colony grows, the cap widens and shades its surroundings; leave space around it.
• Water parameters: Salinity 1.024–1.026; KH 7–11 dKH, calcium 400–450 mg/L, magnesium 1250–1350 mg/L. It is far more tolerant of nitrate and phosphate than stony corals; in completely nutrient-free water its color fades.
• Carbon: In an aquarium with leather corals, regularly replacing the activated carbon reduces the terpene-type compounds released into the water.

It gets most of its nutrition from the photosynthesis of zooxanthellae algae. It also captures fine particles and dissolved nutrients from the water. Direct feeding is not needed; regular fish feeding and stable water are enough.

It fights not with tentacles but chemically: the terpenoid compounds it releases into the water can slow the growth of nearby corals, especially SPS such as Acropora and Montipora and some LPS, or make their tissue recede. Keep stony corals at least 15–20 cm away, use activated carbon and avoid keeping many leather corals together with stony corals in a small aquarium. It is itself vulnerable to long-tentacled LPS such as Euphyllia and to anemones.

It lives with fish and the cleanup crew without problems. Some dwarf angelfish and butterflyfish may pick at the polyps.

It is easy to propagate in the aquarium. A slice is cut from the cap, or the stalk is cut through entirely and the cap tied to a separate stone; the cut piece is secured to a stone with a toothpick, rubber band or mesh and attaches within a few weeks. The cutting should be done in a separate container; the chemicals and mucus released from the cuts must not get into the main aquarium. Daughter colonies can also form on their own at the base of the stalk.

• Staying closed for days: The colony periodically shrinks, a shiny waxy film covers its surface and it does not open for anywhere from a few days to a week. This is the natural shedding of leather corals; once the film sloughs off in the flow, the polyps open.
• Bending and drooping: A newly placed or relocated colony bends its stalk; it straightens up within a few days.
• Darkening and rotting: If a softening, browning area appears on the stalk or cap, cut it off and discard it immediately; rotting tissue fouls the water quickly.