the owner of the fish will see the stripes when the fish becomes comfortable and then will be able to see if the bars form a Y or not.

I was just referring to the general notion that caudal spot is the best way to tell festae from uro...I've seen juvenile festae that people have sworn up and down were uro because the spot looked larger than it should but the bars clearly formed a Y and as the fish grew the caudal spot stayed proportionally smaller than the caudal peduncle as it should on festae.
and of course this only works with juveniles anyway because male festae hardly ever show their stripes as they get past say 4" or so, but then again that's another sure fire way to tell it's festae and not uro.