Updated 10/2017 see below Alright, Over the years I have had 6 total yellow belly regal angels. I have successfully gotten three TRUE red sea regals (sourced from NY Aquatics) and also three Sumatra yellow belly regal angels that did NOT make it. More information, the Sumatra regals allegedly "ate" prior to arrival. One did come from NyAquatic and was fat and healthy appearing when it arrived. It did NOT eat and was dead in 24 hours while everything else continued to do fantastic. The other two were sourced from other vendors and they also never ate and did not survive 7 days. My red sea regals ALL survived, even in QT with lots of cupramine (the sumatra regals never made it long enough for me to ramp up cupramine, I also wait until they are eating and it never happened). I killed two of my red sea regals during TTM. They went through with other fish, and died of ammonia. The first died on day ONE (fed too much and too many fish with it) and the second died on the FINAL day of TTM, after I fed too heavily the night before. The lesson is that these fish CAN handle TTM but they need LARGE tanks/bins and feed VERY conservatively and remove ALL excess food. You should do this anyway but they're very sensitive to ammonia. Same with Chevron tangs. So how does one tell the difference between the two? Well, for one the price. Sumatra yellow bellies cost a lot less. They can be had for $100-$250. True red sea are $210-500. Red Sea Regals: Have "cleaner" darker markings around the eyes. Their stripes are outlined by darker blue almost approaching black. They also seem to have more red markings on their anal fins. They tend to be a hair more "orange" but this is not a reliable way to tell. The EASIEST way is the color of the hilighted blue markings on the stripes and face. Red Sea Regals have a "cleaner" face with darker markings. They also generally have slightly "straighter" stripes (less curved backward). Sumatra Yellow Belly regals (and perhaps others) Have a lighter aqua colored stripes. Their face is also broken up and more noticeably striped as a result of this much lighter colored stripe. Their anal fins can be differing amounts of red on them, and their anal fin itself tends to be "larger". Notice the overall shape difference. Notice the blue markings look to be "glowing" aqua, and the markings near the eye are very obvious. Neither variant is any more or less likely to have misbars or anything like that, IME. Here are some Red Sea regals. Here are sumatra yellow belly regals I honestly have no other experience with other variants of regal angels, so perhaps a few others fall in to this category. But after seeing several, and owning 6 total, I wanted to share my experience and observations. What experiences do you guys have? I hope this is helpful! ***10/17 update: Another few Regals later, my observations are the same. I’ve lost two Red Sea since, one due to power outage. I receive another Sumatra next week, figured I’d challenge my theory again. I’ve seen several more angels since then and can pick a Sumatra or similar region out of a lineup with ease!