Polyp extension

[kimoyo]

Several of my corals have their polyps retracted.

When and why do corals retract their polyps?

 

[joe]

by corals do you meen all,
or by extended polyps, im assuming your talking about SPS. rite?

 

[kimoyo]

Yeah I'm speaking about sps. My mille's seem fine buy my yongei, torts, tenuis, and others are retracted. I'm not sure if its the lights, or that I just added some 2-part yesterday, or my fish that I added back to the tank earlier this week.

So are there specific reasons for polyp retraction.

 

[ShaunW]

Reason 1.

Red bugs

 

[ShaunW]

Reason 2.

Chemical toxicity via external additions and internal release (coral battles).

 

[ShaunW]

Reason 3.

HIGH nutrient build up.

 

[nanoreefer22]

I agree with reason 1....they seemed to stay away from my millis when I got them, but got to the others.
-Kris

 

[ShaunW]

Reason 4.

Changes in the homostasis/equilibrium present in the tank, i.e. temp, salinity, light.

 

[kimoyo]

Reason 4.

Changes in the homostasis/equilibrium present in the tank, i.e. temp, salinity, light.

So they will retract them when the lights come on? I'm thinking this might be my issue, because the lights just turned on and the polyps seem to be starting to extend again.

I'm also worried about fish nipping.

 

[ShaunW]

So they will retract them when the lights come on? I'm thinking this might be my issue, because the lights just turned on and the polyps seem to be starting to extend again.

I'm also worried about fish nipping.

What your witnessing is a protective response. Reefs are active during the day, fish are around picking at corals (and coral polyps, i.e. butterfly fish). You must have observed the difference between night time polyp extention (when the reef is sessile and plankton and bacterioplankton are most available) and day time polyp extension?!

 

[ShaunW]

Reason 5.

Fish picking! (Paul that is your addition, ).

 

[jackson6745]

Reason 6.

You can't stop touching your corals.

there have been a couple times when I messed up with my dosing and my Alk and or MG were VERY high (alk 15dkh+ Mag 1500ppm+). Polyps on all SPS were retracted until levels lowered.

 

[ShaunW]

Reason 7.

Acro flatworms.

 

[ShaunW]

Reason 8.

Too much direct flow! Sand storms.

 

[kimoyo]

Thanks for the info everyone.