BTA tentacles changing under different lighting conditions

[Susan Lohrer]

I'm using a TaoTronics AL01 with the blue lights on from 8 a.m. to 4 p.m. and both blue and white lights on from 10 a.m. to 2 p.m.

The light fixture is about 9 inches above the water surface, and the BTA hangs out about 14 inches below the water surface.

When just the blue lights are on, the BTA's tentacles are about an inch or so long and bubbly. When the white lights come on (with the blue lights still on), it gradually stretches upward and elongates its tentacles. Then when the white lights go off in the afternoon, it gradually returns to its morning posture and bubbliness.

This isn't a problem (at least I don't think it is). But I'm curious as to why it would stretch upward when it has both lights on.

 

[D-Nak]

No one knows why BTAs take on a bulbous appearance. Some believe that it has to do with surface area. If this is true, then when BTAs stretch their tentacles, they are increasing their surface area which allows the symbiotic zooxanthellae more access to its food source (light).

So, in your case, the nem is sensing that there is light (white light, with more useable energy) and is extending its tentacles.

Keep in mind that this is more theory and anecdote, than scientific fact.