I had one that grew from 4” to 12” in a year but I had a wild tomato clownfish that would bring food to it from the surface or other side of the tank (unlike my tank bred ocellaris clowns now that steal food from their host).
Keep in mind they look cool when they come in white (bleached) with purple tips but they end up shoe leather brown.
Mine stayed with its foot in the sand for a while and then found a place in the rock work. They have a large flat plate shape that sort of folds in half at night and your clownfish will sleep inside it like a fish taco.