Leather Coral

[spikey]

Can anyone explain to me why during the day my leather is 20cm lush beautiful coral during the day; however, at night it curls up like it is about to die. It is obviously what this type of coral does at night, I would just to know WHY???

[HN1]

It is completely normal. Most corals contain zoanthalae and are photosynthetic so they retract their polyps when there is no light.

[melosu58]

Corals have to cut back like we do at night time. What you are describing is completely normal.

[Drewbie]

sleep / protection has always been my guess

[spikey]

So you think that it pumps out the water? And it is like a protection think. I think it is fascinating to see it happen. I note the other corals do this to a smaller extent; and I expected it to happen. It was just this one that fascinated me to think; WHY????

[Atari]

It would waste a lot of energy to stay expanded all the time, especially when there isn't enough light to make it back.

[mandown123]

the polyps extend to feed and take in light. during the night time, they conserve energy, so they draw polyps in and such "sleeping" behaviors.

Some corals extend feeders during the night after extending light gathering polyps during the day. An example of this would be a trumpet or candy cane coral. Polyps fat and plump during the day, lights out -> feeder tentacles extend and gather food from the water column. Most every coral has daytime/nighttime behaviors.