Slower than a herd of turtles stampeding through peanut butter! Lol, I have no luck growing it, but my friend kept some in a high-light half-gallon cube (no ferts) and it grew really fast, also algae grew on it.

 

It depends on how much you want it to grow, as the saying goes, a watched pot never boils.

I'd say it grows pretty fast for a moss. you might get an inch of growth per month, depending on the conditions.

 

Probably depends on the set-up, but for me it grows steadily. I never notice it growing but then it's like "whoa hey. there is more moss than there used to be."

So it's slower than most of my stem plants, but faster than anubias.

Though I guess it's harder to notice when the moss is left in a tangled blob. I think I notice growth with flame moss more easily since it grows a bit more upwards

 

What's a good fast growing plant to have for a betta fry grow out tank>