Why do these GSP look so different? Is it different species?

[saltyfish24]

From photos of GSP online, I see vastly different looking GSP. Some are very long, and the green polyps seem thick. Others have very short, thing polyps. Wondering if there are different species of GSP? Or are they all the same species, just growing differently in different tank conditions?

I'd like to get longers, thicker looking GSP. Not sure if I'd have to start off with that type first.

 

[Llyod276]

Nope, all that is flow and lighting and age. After a awhile of growth the tentacles on the gsp will get longer. New polyps will be small, older will be larger/longer.

 

[BryanM]

There are 2 or 3 different families of GSP.