Don't try to keep upgrading tanks. Just start by getting one tank and set it up properly so that you don't upgrading. In many cases, life gets in the way of upgrading. These fish grow 1" per month in the first year of life, so you'll end up with a 12" fish if you get one as a juvenile.
Permanent tank should have 24" width (120g, 180g, I think some 150g, and most of the 200+g tanks).
Feed a variety of crustaceans and keep up with the water changes.
Tankmates are not recommended.