My puffer is growing, and I'm looking for a 55 gallon for him/her. I'm curious, how long does it take for a GSP to become an "adult". I don't want to stunt his/her growth, but I'm also waiting for a "perfect" tank on Craigslist. Any thoughts on how long I can safely keep a currently 1.5"-2" GSP in a 27-30 gallon tank? Salinity is now at 1.010.