Is there a guide to look at when choosing certain species when fish are at around 1.5 to 3 inch in size, to make sure you are getting the true species at the LFS or is just impossible to tell? For instance I was looking at green severums, red shoulder, and other types and was wondering if there was a way to tell if they are in fact the true species they say they are as they are hard to tell at such a small size.