What is this?

[NIVLEM09]

are they silk like strings or cotton like?

[albert_dao]

Mesenteric filaments, aka sweeper tentacles

Perfectly normal.

[Reef Pilot]

Originally Posted by albert_dao

Mesenteric filaments, aka sweeper tentacles

Perfectly normal.

Yup, I think that's it. Did a little search on these, and found some that look exactly mine.

Thanks Albert. You definitely know your stuff...

[NIVLEM09]

the other cotton like strings are called digitate hydroids...

[Reef Pilot]

Originally Posted by NIVLEM09

the other cotton like strings are called digitate hydroids...

Nope, just looked these up, too, and definitely not the same. Thanks for the suggestion, though.

[Reef Pilot]

Originally Posted by NIVLEM09

are they silk like strings or cotton like?

To me, they seem more silk like (although not sure what difference cotton like is), almost like spider web material. Like I said, they only appeared yesterday morning and this morning. And only from all the corallite tips. Also, I noticed that out of the centre of the corallite, there was about a 1 mm white extension sticking out which is where the thread originates from. This white extension is normally flush with the tip during the day, not protruding like that. Once the lights ramp up in the morning, these little white extensions all pull back inside.

I also noticed where these little threads meet another one, they join, making one thread between two corallites. Maybe they are spawning???

This coral has very nice colour and is growing very fast (about an inch in just the last month). So it looks very healthy, from what I can tell.