Polyp Extension: Whaaat????!!

[watchguy123]

I see wonderful polyp extension an hour or two after the lights go out but very minimal during the day. So on occasion when I have turned the lights back on at night, I notice the polyps retreat just after seemingly a few minutes.

So why do polyps extend, I have always assumed for feeding. And both how and why do polyps retreat with lights on. And why do some tanks have great polyp extension during daylight hours and others don't

 

[kevin_e]

They extend their feeding polyps when the lights go out to feed. Polyps will retreat, but not fully.

 

[Pife]

I bet you have something nipping them during the day.

 

[scrapz]

I bet you have something nipping them during the day.

Probably that, I found out my yellow tang nips at my SPS in the display.

 

[Myka]

I had a Flame Angel that nipped all my SPS during the day. He didn't touch them for the first few months, but by a year he was nipping all the corals all day long. He just did drive-by nips, like he'd swim along and pass a coral and nip it on the way by without even stopping. I didn't notice for quite awhile because he did it so quick. Sit down and watch the fish where they can't see you, and you might find someone nipping or drive-by nipping like mine did.

 

[SPS911]

I had a Flame Angel that nipped all my SPS during the day. He didn't touch them for the first few months, but by a year he was nipping all the corals all day long. He just did drive-by nips, like he'd swim along and pass a coral and nip it on the way by without even stopping. I didn't notice for quite awhile because he did it so quick. Sit down and watch the fish where they can't see you, and you might find someone nipping or drive-by nipping like mine did.

Was going to ask you if you had any dwarf angels.....Had the same exact experience as Myka in one of my older tanks.

 

[watchguy123]

I bet you have something nipping them during the day.

The likelihood is that one of my angels is nipping but with all the time staring at the tank, I have simply not witnessed it.

But how does turning on the tank lights cause polyp retraction. Physiologically, what is happening and how have they learned to respond to that stimuli.

 

[vuqchu]

The likelihood is that one of my angels is nipping but with all the time staring at the tank, I have simply not witnessed it.

But how does turning on the tank lights cause polyp retraction. Physiologically, what is happening and how have they learned to respond to that stimuli.

Defense mechanism. Lights on, nippers out and about. Lights off, nippers in hiding sleeping so corals feel more safe. Just my opinion.

 

[rvareef]

my angels feed during the day, so the corals have associated daylight with nipping, get rid of the nippers and I bet you will have better PE during the day

 

[MichaelW]

my angel may occasionally nip but these little nips don't really seen to bother the health of the acros... Maybe less pe but nothing damaging.

 

[watchguy123]

But how does an sps have the biological mechanism to retract polyps in response to light.

 

[sahin]

The likelihood is that one of my angels is nipping but with all the time staring at the tank, I have simply not witnessed it.

But how does turning on the tank lights cause polyp retraction. Physiologically, what is happening and how have they learned to respond to that stimuli.

I'd put my money on one of the angels. I put a nipper in the tank last year and after a few nips for a few days the SPS retracted their polyps throughout the day...MOST of the SPS...even when the fish wasnt nipping.

I dont know how...but the corals maybe sense something because almost all the SPS had retracted polyps even ones I was sure the fish wasnt nipping.

But how does an sps have the biological mechanism to retract polyps in response to light.

I believe so. At night the PE on some of my corals go crazy 1-1.5cm. Daytime the polys are shorter...but my SPS tanks have always had crazy PE.

 

[A.G]

for me ,
I found that angels do nip even if you dont witness them.
I found that intense light cause polyps to retract.

So if you had a coral that had great polyp extinsion during the day before and now it does not. Then there is a reason.
Just my 0,2

 

[reefmutt]

My pe has very noticeably reduced since the addition of a dwarf golden angel..
I do see him go right over to extended polyps and take a bite.
He is constantly nipping all over the tank.. Corals, rocks, sponges whatever.. It's constant and indiscriminate.
With lights out, the pe is quite amazing in some corals..
I have found that the fastest growing corals tend to have the most pe at night..