Well, there are not any subspecies of anaconda...the greens are a separate species.
If you are getting granite anacondas they are from the Mark Petros line of yellows and they are the most amazing eaters I have ever seen (I am thinking of sharing a McGriddle with them...and I bet they would take it). They are extremely easy to keep if you know how to deal with a larger snake that will keep you on your toes. I keep them without large water dishes (like Kelly Haller does with his greens) and they eat great and always shed in one perfect piece.
Only tip I really have for you is to keep it perfectly clean in their enclosure. And this will be a tough task because my yellows are by far my biggest mess makers in my snake room.
