How fast do corals frags grow?

I am curious how fast do frags grow. I am guessing it also depends on what type of corals, foods, lighting, etc???

 

I do not believe there is any constant really. Too many variables as you already mentioned, water chemistry playing a big part as well.

As a generalization I think it's safe to say that soft corals such GSP, xenia, colt, kenya tree, sacrophytons (the leathers) are the fastest growers.

LPS such as Duncan, the Euphyllias are moderately fast grows under the right conditions where Chalice would probably considered a slow grower.

Acropora or other SPS, under the right conditions Montipora and Pocillopora as well as Seriatopora hystrix are all considered some of the faster growing sps. Red Planet, Valida and some Millepora are some of the faster growing Acropora if you like watching/waiting for a pot of water to boil.

 

I like watching grass grow. What coral would be good for me?

As far a variables. Lighting, Water Flow, Water Quality, Nutrients(inc food), Calcium and other elements all make a difference.
Some more than others for the different coral groups Corailine mentioned.

Any type of coral you were wondering about?

 

Thank you so much for the response everyone. I appreciate that.