??

[nano]

I installed two 165 watt LED 14K lights from tao-tronics. They were on the tank about 6 weeks when i noticed this growth here appearing . The picture of it was 3months after the new lights were installed. The system was 4years old then ,and no new stock was added. I couldn't get a id on it at the time . I came across this picture ,and thought i should ask.
what is it?

 

[Irsug1]

Maybe feather algae

 

[kateater]

Appears to resemble a fern caulerpa

 

[twilliard]

Appears to resemble a fern caulerpa

Indeed

 

[brandon429]

calurpa (said in cool way circa 2014)

 

[nano]

I thought caulerpa had like little bubbles like growth on a stringy stem. I had some ,and it was a tangled mess and really grew fast. This stuff here had quite a slower growth rate. But someone did comment a few years ago that it looked like a native to the Pacific side ,and was evasive. ..? I'm not sure. No one (tank inhabitants ) seemed to eat or bother with it.