Why is my frogspawn doing this?

[seandre3000]

Noticed lastnight my frogspawn had a bubble in the center. It’s back to normal today. What was it doing?

 

[Timfish]

It's not very clear but why corals "bubble" or "bounce" is up in the air. Light spectrum is a factor though.

A Novel Investigation of a Blister-Like Syndrome in Aquarium Echinopora lamellosa

This study investigates potential causes of a novel blister-like syndrome in the plating coral Echinopora lamellosa. Visual inspections of this novel coral syndrome showed no obvious signs of macroparasites and the blisters themselves manifested as fluid-filled sacs on the surface of the coral...

journals.plos.org

 

[kevgib67]

I haven’t seen with my torches but a big bubble appears on my hammers and frogspawn when they are beginning to split.

 

[vetteguy53081]

Noticed lastnight my frogspawn had a bubble in the center. It’s back to normal today. What was it doing?

My hammers do this occasionally when fed or over fed and also ive seen this more than once when there is lack of flow. Torches do best mid-tank or above opposed to lower part of tank where there is less PAR and flow