That's actually not a problem if your angler is small enough. But you have to be willing to upgrade in time or plan on giving ownership to someone else as well as provide excellent husbandry.
This was my guy in a 6g.
This is my guy in a 3g... been there for 6 months or more. I'm not at home to look at my log so I don't remember exactly. He's going to be in there for quite a bit more time yet. So he'll definately spend a year in there.
So, if you buy them small enough they can keep them in smaller tanks while they grow.... depending on how small you get them, that time could definately be a year.