What makes BTA bubbles bubble?

[planedoc]

Usually my BTA that was once one 3" Anemone has split twice and I now have two 12" ones in this tank and an 8" and growing in my other tank. Usually 1/3 to 1/2 (at the most) of the tentacles have actual bubbles on them. Today for reasons I don't know all of the tentacles have bubbles. Does anyone know or have an idea on what makes them fill or deflate?
Yesterday in the morning the one on the left was gone. It appeared in the late afternoon on the far left on the other side of a rock. Last night it moved back to where its been for the last year where it is now . The one on the right has never moved in two years. Just curious if it means they want to be feed or if they are full. I feed them 4 weeks ago. Usually I only feed every 8 to 12 weeks.

 

[m0nkie]

not 100% sure, but mine bubbles when there's more lights. all of mine would be bubbly. When I did a 3 day black out and all 3 RBTA were thin tentacles. 4th day at light on, they all got bubbly again.

 

[Drae]

I read somewhere that nobody knows why they do this. It differs from specimen to specimen.

 

[vikubz]

I had an RBTA in a tank with egg crate over the top to keep fish from jumping. When I lost that fish I removed the egg crate and within a week it had developed big bubble tips on all its tentacles. I didn't think the egg crate would make that much of a difference, but it had a huge effect. Seems light is a big factor.

 

[Timfish]

Lighting is part of the equation but there are other factors a BTA will take into consideration on deciding if, when and how much to bubble. I've seen clones next to each other, one bubbles and the other doesn't. Specimen in one tank bubbles at moderate PAR and a specimen from the same clone line won't bubble under brighter light in a different tank with an identical light fixture. If somebody figures it out tell me so I can right a book on it and become famous.

 

[shesacharmer]

I feed mine twice a week!

 

[Bryopsis]

What's your nitrates at? I've always found that any coral with soft tissues/tentacles seems to expand more under the presence of lower flow and nitrates.

 

[planedoc]

I always read zero nitrates. I've had tank for 3 years but the rock has been captive for around 10 years. Very stable system. They are looking good again today

 

[igot2gats]

I read somewhere that nobody knows why they do this. It differs from specimen to specimen.

This is the answer. It's on the 'nem to bubble if it wishes.