[Help]How to know the all of difference between grade A, AA and AAA of BD stingray

I think things are different today vs. a few years ago. Due to selective breeding, physical characteristics that people looked for are now gone. Before a dead give away of a higher grade fish would be 3 rows of spots around the perimeter. Now, it's all about the size of the spots and how many. You will know a great fish when you see it. But just like anything else, begin by looking at their parents. This will tell you a lot by itself. For me, belly spots is a must. Unfortunately, most BD's seems to be hybridized in order to achieve the ultimate offspring. Juveniles spotting can changed dramatically, best to buy a slightly older fish if you truly want something nice.