Argentea grow very slowly. Put 5-6 of them in a 90, if they're 2-3 inch, you've got a year until they're 4-6 inches. At least, that's my experience with them. Rapps has some for sale right now.
I accidently over fed him this morning. I threw in a bunch of shrimp pellets for the striped raph and the arg ended up getting all of it. Can he be sexed if the shaft/tube what ever its called is sticking out ? It looks pointy like a triangle