SPS Polyp Extension Thread

[250G]

Let chat about SPS polyp extension (PE).

So what does PE mean to you??? Is it a good thing? Is poor poly extension a indicator of potential problems?

Why is it one really hairy acro in one persons tank can have little PE in another persons tank? Also, what product gets your SPS polyps fired up the most?

Generally speaking I feel I have average to below average PE, but the corals that have significant PE, well they are as hairy as they come. Thanks.

[kev apsley]

the polyp is the actual animal inside the calcareous skeleton, like an anemone living inside a skeletal fortress. So yes you want to see good PE wether it's during the daytime or night time. Poor PE is a sign of a stress of some sort.

Lot's of PE make me Happy!

[nwrogers]

I think lots of polyp extension is a good thing personally. I have found that the only times I have had bad PE is when I had a fish that was nipping at them or when I had red bugs. Within hours of removing the bad fish I had great PE so I know that the stress that fish was causing is was the reason for my bad PE. Before removing that fish I didn’t even know monti caps had polyps on the bottom! Then I slowly lost PE again until I discover I had red bugs. Within hours of the red bug treatment the PE was great again. I think bad PE on many, not all, corals is a sign of stress. This stress may be natural since I am sure stony corals get picked on in the wild but because the system is so small it may be more stressful than the coral can handle. After treating for red bugs I also notice coral coloration really improving as well but that is for another thread. So I think in an ideal predator/pest free environment you will have great PE and your corals will be very happy. Bad PE doesn’t mean that your coral is sick it just means something is picking on it IMO. Corals have adapted to being picked on in the wild so being picked on in captivity may not be so bad so long as it is not constant. On another note I have noticed my growth as improved since removing the fish and the red bugs so that is another thing that leads me to believe that PE equals happy coral :)

[manderx]

i use nightime axial polyp size to spot-judge how my tank is doing. when it's doing well, the polyps on the tips are *HUGE*. i figure more growth = more respiration = more need for gas exchange.

[kev apsley]

<a href=showthread.php?s=&postid=10602809#post10602809 target=_blank>Originally posted</a> by manderx
i use nightime axial polyp size to spot-judge how my tank is doing. when it's doing well, the polyps on the tips are *HUGE*. i figure more growth = more respiration = more need for gas exchange.

excellent point!

[MiddletonMark]

While I look at night-time PE to see if it looks `good' or if concerned over problems ... I don't put much emphasis on it.

IME, daytime polyp extension has not had a close correlation with overall tank health + growth. I've had poor PE and great color/growth over periods - and good/ok PE with problems/recession occurring. That's my tank, perhaps not a universal .... but excepting only red bugs [which caused minimal day + night PE], I've not felt that it tells me much.

But, that's just my experience with my tank. :)

[Horace]

I find that my corals tend to be better off if good PE is observed. Typically if I have low PE on a coral, it is because something is out of whack. However, it has been pointed out many times, good PE is not allways a sign of good things. For example a coral can have very long PE just because it has low o2 and needs to respirate. That being said, I think good PE is GENERALLY a good sign. Low to No PE IME often indicates stress of some kind.

[stony_corals]

There's no corrolation between PE and coral health... PE can be due to feeding response, agression, and gas exchange. Between the first and the last, you won't know.

[250G]

Lots of thoughts from an experienced group. Thanks.

So I get really good PE at night, and just average at best during the day. Feeding response to cyclopeeze is strong. Is it possible that my "perceived" reduced PE is because of higher O2 levels in the tank, and a lot of flow?

I push over 2000GPH though my external overflow and have increased my circulation 3 months ago (and am still pretty happy with the tank, more than 90% of the corals look really happy).
A buddy's tank has less O2 I would guess (800-1000GPH though the overflow) and maybe half the x's circulation I have and has a ton more PE (on some of the very same corals)...at the same time I know there could be alot of other variables.

250

[michika]

Aside from stress, and pests, I do also find that polyp extension is a function of flow. I have a few corals which have great polyp extension on one side, and little, or even none on the other side. These are all corals who recenly had some of their usual flow blocked off by other growth.

http://i21.photobucket.com/albums/b286/michika/PICT0008-1.jpg

[crazedreefer]

I feel PE is a good sign of coral health...whether it be in the day time or night time. I feel the reason why PE is better in night on a general wide spread basis, is that this is a natural occurrence in the ocean, polyps tend to be retracted during the day due to polyp eating fish being out more during the day. Most fish that feed off polyps are hiding and resting when the sun is down, so it would make sense as protection of their polyps they extend when it is "safest"...This is just an assumption but why I think polyps show better extension at night.

[dukes707]

i think good PE is a sign of coral health, to an extent. when everything is homeostatic in my system then PE is good, not great, but good. i dont get outrageous PE like i see in some others' tanks. i happen to think that my alk levels have somthing to do with it, sort of an indicator of my tanks stability. when my alk drops to 7-8 dkH i see a reduction in PE, and when i bump it up with some baking soda to about 9 dkH PE is awesome. flow dramatically increased the amount of PE i saw as well. after adding a koralia 4 and a couple mj's and redirected flow to be more random and crashing then PE also got better. i contribute below average PE during the day to my potters angel, and striped damsel. although i noticed they only go for colored polyps, the brown ones they take no interest in for some strange reason. but thats a topic for another discussion.
i also was under the impression that polyps come out for feeding and respiration. so is poor PE a sign of a nutrient and oxygen rich system. do they not extend as well or as often cause they are well fed and respirating well enough? i noticed that when my corals are really colorful and going through a period of growth PE isnt necessarily exploding -average at best. does that mean my corals arent happy, or are stressed? i think not.
another example is in my buddy's tank. his reef is constantly being stressed out because of bad husbandry (like i say to each his own), but his corals polyps are jumping outta their shell. is that a sign of good coral health?
all in all i think PE is a good thing, but not necessarily a sign of healthy corals all the time. lots of contributing factors will determine the amount and duration of PE certain corals have. cyclopeeze, helps lots...and yes corals do eat. IMHO.

dukes

[stony_corals]

Some species do, in the wild exhibit day time PE, others do not. Why would Alk effect PE? This is my whole point why PE is meaningless..... you do not know if it is a gas exchange response at a particular occurance or feeding or what.... yes, they do feeding, in fact, with sps, a greater portion of their energy budgets are from heterotrophic feeding (bacteria, zooplankton) versus autotrophic (photosythesis). That PE is a function of gas exchange, feeding, agression, species specific, etc. is a scientific fact. Feeding may be an easy one to identify when you put cyclopeese in the water, but at any point in time will you know why for certain and whether that is bad (animal trying to increase gas exchange) or not (just trying to catch some food) you will not know and to claim that good PE = good health is not accurate.

[fish02]

I always wondered about PE as a determining factor of health also. All of my SPS have great PE, but at night on one of my SPS where the new growth is PE is ridiculous at almost an eighth of an inch. The other thing I noticed is that it started to turn a creme white and the tips are turning purple from the original brown green color when I got it. (there is a story behind this acro that explains only the tips having insane PE, but not really important.)

The other acro I have doesn't have nearly the PE the one above has but it is also gaining amazing color of creme white with purple tips from the same brownish green. Makes me think they are the same acro.

So the question is, is one healthier than the other even though they are both coloring up at the same rate and time based soley on PE? I don't know, but this would lead me to believe that PE isn't a determining factor of overall health.

[stony_corals]

fish02, no it's not.... I must not be writting too clear or concise....

[fish02]

No worries stony_corals. I started typing my post before you or something because before I started typing your response wasn't there. Only after my post went up did I see yours. I got kinda distracted by an almost overflowing protein skimmer.

[agent6473]

I've noticed increased PE since I've switched to a 2x250w AB 10k + 2x54w actinic as opposed to my original 2x250w phoenix 14k. There was good PE using the phoenix, but there seems to be more overall on all of the corals since the switch.