retarded zoas

hope subect line didnt offend anyone.

i added two different zoa frags to my tank a while ago. both are doing well and expanding but one is doing way better than the other and i am curious why that may be. they are in almost the same spot, low in the tank, identical flow and same light. the retarded one is about an inch higher up the rock. the colony on the right has covered the plug and moved onto the rock while the left colony has barely moved from the top of the plug.

30 gallons
t5 -156 watts
parameters are all stable
i dont test my calcium very often but i do 10% water changes every week.
i also dont test pH and alk very often because i used to but they were always stable

im not so much worried about this situation as much as intellectually curious

forgot to post this:
im talking about the red and green(retarded) ones, not the blue ones

Zoanthids are collected from all over the tropical regions of the oceans, some are cold water relatively speaking and some aren't, some are deepwater and some aren't. Thats just the nature of them, some multiply fast and become very prolific and some grow rather slow. Give them time they will fill out.

They are very nice looking zoas BTW.

They don't look unhealthy!! Is there a possibility that there is a predator on the 'retarded' colony? Have you tried dipping it?

I think they are just two different types and have different growing behaviors.

+1 ryan and decan, I think they are just 2 diffrent types and are gonna grow at diffrent speeds.

I think Ryan nailed this one.
Judging from the pic.It dont look like any of em have been eaten.

I had one frag that spread over a rock the size of a softball, while another frag only grew a few polyps over the same amount of time.

The ''mentally challenged'' zoas look good to me.Give them more time otherwise they look healthy.