Polyp extension at night vs day.....

[rovster]

Is it normal for some SPS to extend polyps at night vs day. If so, is there a reason for that. I've read it may have to do with lighting or feeding. Reason I ask is I have a number of SPS in my nano. There are 2 in particular that show little polyp extension during the day, but at night, WHOAA! Crazy polyps. Its one acro in particular, and a red echinate (red dragon maricultured). The acro in question is growing very well, and has a huge base and is starting to shoot up branches, so seems happy. Just a curiosity of mine. Thanks!

 

[Josh40996]

Some sps polyps only extend during the night as this is when it is less likely for fish to eat the polyp as most will be sleeping.

 

[rovster]

Only a clownfish in there, but I'll buy the fact that some just extend at night. Thanks for the reply. The polyps at the base and on the body extend during the day, but the larger polyps at the tips of the coralites only come out at night.

 

[epicurus84]

Completely normal this is what they also do in the wild.

 

[Surgical]

Keep in mind that most zooplankton is active at night. This is why polyps extend at night.

 

[rovster]

Thank you very much. I was not overly worried, just curious. I wish they would extend polyps like that during the day. It looks awesome! Most of my acros have good polyp extension during the daytime. Something just looks "off" when they don't, LOL! I'm currently going through a low nutrient, paling issue now becuase my tank is fallow, so I wanted to ask just in case. Been trying to thow crap in there to keep the corals fed, but what a difference when there is a fish present!

 

[Dexters Reef]

Perfectly normal for certain SPS. My purple w/ green polyp monticulosa has PE only at night. Within 20 min of the lights coming on, the polyps are all retracted. About 1 hour after my halides go off, it starts to come out again.

Good luck!