HOW BIG?

[Mattcomptonassvanhorn]

How big will a maroon clown get in 10 gallon because when he gets big enouggh I want to move him into my 55 witch have fish that if I put him in now would eat him like a fat kid would a cupcake.

[EZHOOPS]

he'll grow normally if he's alone and regular water changes are done, feed him to saturation, it will take some time for him to reach adult size though, I would say about 2-3 yrs IME
good luck