they are all below 6". the 2 big ones I bought at approx. 5", and if they've grown at all, its immeasurable. I truly believe it has to do with my water's chemical composition differing from the native range of the fish. I've always wondered about that so I figured I'd share what I believed to be possible evidence here haha.
P.S. my nitrates are never above 10, and they receive 2x water changes a week without fail.
Yeah, I'd agree that seems slow imo.