polyp extension

[Reefpestsolutions]

Is polyp extension a sign of great coral health or self defense. Dose it truly mean a coral is happy or mad? I want to see some scientific evidence of polyp extension, is the coral feeding?

 

[KoleTang]

Polyp extension refers to the coral (polyp) opening. A trachyphilia is one polyp. An acropora colony consists of hundreds of polyps. The polyps on a healthy coral will be open most of the time.

Feeding tentacles are a different story and only come out when feeding.

 

[Reefing Madness]

Evidence is when you see other corals of the same all extended and yours is squished up, because it doesn't like this or that.
Sweeper Tentacles are a defense mechanism of corals.
Chucks Addition/ Coral Aggression
Mechanisms of Coral Aggression and How to Control It