How much light and flow does Open brain coral need?

Stony coral · LPS, low light at roughly 50–80 µmol·m⁻²·s⁻¹ PAR, with low flow. Light and flow must match: high light with weak flow burns tips, strong flow with weak light thins the tissue.

Will Open brain coral attack neighbouring corals?

It has sweeper tentacles: at night it extends tentacles several times its own width and burns whatever they reach. Leave at least one adult diameter between it and its neighbours.

Does Open brain coral need feeding?

Yes. Photosynthesis alone will not sustain it; feed planktonic or finely chopped food regularly, little and often. Overfeeding fouls the water faster than underfeeding.

What water parameters does Open brain coral need?

24–26 °C, specific gravity 1.024–1.026, 7–9 dKH, 400–450 mg/L calcium, 1250–1350 mg/L magnesium. That is only 2 dKH wide, so stability matters more than hitting a particular number.

Is Open brain coral a good beginner coral?

Difficulty: moderate. Growth: slow. Place it in the foreground. Spacing: sit it on the sand or a low flat rock and do not glue it down; it moves by inflating, and sharp rubble cuts the underside.

G-03 / 11Marine

Open brain coral开放脑珊瑚

Trachyphyllia geoffroyi · Merulinidae

Open brain coral: a free-living brain coral on the sand that moves by inflating its tissue, and it must be fed.

Illustration to come

G-03 / 11 · Open brain coral Trachyphyllia geoffroyi

SpecificationsCoral atlas

Name: 开放脑珊瑚
Scientific name: Trachyphyllia geoffroyi
Family: Merulinidae
Origin: Sandy bottoms and reef slopes of the Indo-Pacific, including Indonesia, the Philippines and the Great Barrier Reef
Type: Stony coral · LPS
Light: Low light
PAR: 50–80
Flow: Low flow
Aggression: Sweeper tentacles
Feeding: Feeding required
Alkalinity: 7–9 dKH
Calcium: 400–450 mg/L
Magnesium: 1250–1350 mg/L
Salinity: 1.024–1.026 SG
Growth: Slow
Placement: Foreground
Level: Moderate

Water requirementsMarine

Temp.24–26 °C

pH8.1–8.4

Salinity1.024–1.026 SG

Alkalinity7–9 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Keeping notes

1Spacing: sit it on the sand or a low flat rock and do not glue it down; it moves by inflating, and sharp rubble cuts the underside.
2Flow: low to medium; strong flow keeps sand blasting against it and abrades the underside.
3Feeding: required — shrimp once or twice a week; without it the coral slowly shrinks until skeleton shows.
4Water tolerance: not fussy about parameters, but being buried in sand or injured underneath leads quickly to infection and total loss.
5Growth form: mostly figure-eight or plate shaped, with new mouths from central division, adding only a few millimetres a year.

Frequently asked questions

How much light and flow does Open brain coral need?: Stony coral · LPS, low light at roughly 50–80 µmol·m⁻²·s⁻¹ PAR, with low flow. Light and flow must match: high light with weak flow burns tips, strong flow with weak light thins the tissue.
Will Open brain coral attack neighbouring corals?: It has sweeper tentacles: at night it extends tentacles several times its own width and burns whatever they reach. Leave at least one adult diameter between it and its neighbours.
Does Open brain coral need feeding?: Yes. Photosynthesis alone will not sustain it; feed planktonic or finely chopped food regularly, little and often. Overfeeding fouls the water faster than underfeeding.
What water parameters does Open brain coral need?: 24–26 °C, specific gravity 1.024–1.026, 7–9 dKH, 400–450 mg/L calcium, 1250–1350 mg/L magnesium. That is only 2 dKH wide, so stability matters more than hitting a particular number.
Is Open brain coral a good beginner coral?: Difficulty: moderate. Growth: slow. Place it in the foreground. Spacing: sit it on the sand or a low flat rock and do not glue it down; it moves by inflating, and sharp rubble cuts the underside.