where did my PE go?

Definitely watch the flame angel as others have suggested. maybe throw him in the sump for a couple days to see if your PE returns.

Also getting that tank temp down would help, at least shoot for 78, I prefer 75-76. Fans are a GREAT, cheap and easy way to lower tank temp, however evaporation increases exponentially I have found, so make sure you top off more.

 

I have a fan on the tank as is but I went out and picked up a chiller so I'll see if that helps. I just don't see why the flame would only pick on those 2 corals and nothing else? I've had him since my last tank so he's been here a while. I'll keep a close eye though. If the temp doesn't help then I'll put him in the 125 and see if it helps. I have had a bristle worm infestation I've been dealing with so maybe that could be a reason also. I've removed well over 80 large worms and 30 small ones with traps in the last 2 days. I noticed bristleworms were coming from underneath my sunset montipora so maybe they've caused irritation. I know my clams are happier now that there not underneath them around the foot anymore.

 

oh my! I hate bristleworms although I understand they are a good thing but too much of anything usually is not good. Hope that's your culprit

 

the other thing could be stray voltage, I have had that happen before and only a few corals showed signs of it but as I put my hand in to move them a cut on my finger quickly alerted me of the pump having a short in it that was just a little bit of unpleasantness.

 

Me too OFK. I have all my tanks grounded because I've been hit by stray voltage before. Ouch. Lol.

 

Flame Angel. Never saw mine nipping, but as soon as he moved to a new tank the PE came back.

 

+2. I had a bicolor angel (pygmy) and I only saw it go after one coral once for the 6 months I had him. However, I had zero PE on my corals. Once he was removed, bam, polyps were out and proud!

 

PE is primarily a feeding response, but corals will retract to protect against predators. So, mostly likely the coral does not sense any food, or something is preying/nipping on the coral. Does the corals polyps extend at night? That would actually be more natural. In nature, often corals will extend polyps at night when predators are "sleeping" and zooplankton are out and about and retract in the day when there are predators about and less food. In our tanks, corals may learn to extend polyps during the day as well, as we control the predators and often feed during the day.

If the coral is reasonably colorful and growing, it probably isn't an issue, especially if there is PE at night. Some people feel better about having PE during the day though, if so, you may need to feed or dose something that the corals can "smell" or if the issue is the fish, remove it.

 

Good point, about a 1/3 of my coral's PE comes out at night. I've figured out which ones come out at night for feeding and I will try to spot feed them as well.

The corals that were not showing any PE were still encrusting. So I know they were growing, but the lack of PE was my concern.

 

The corals are really colorful and still growing, I'm just used to the polyps always extending. Hooking up the chiller tonight then if need be I'll put the flame in the 125.