Zoa stem size meaning.

[Jake_the_reefer]

So I notice something with my zoanthids that's interesting. I took a bunch of zoanthids from my 20g growout tank that had long stalks and after I moved them into my new 20g display tank they are now flat against the frag plug with almost no stem.
In the growout they were in medium light and high flow and in the new tank they are in medium light medium flow. What causes this?

 

[Ron Reefman]

IMHO long stalks usually means they are reaching for light or to rise above something irritating them.

You say both tanks are "medium" light. Just what does that mean? Do you have PAR levels? Do both tanks have the same fixtures run at the same power levels?