Yellow Angelfish(Centropyge heraldi) reach approx. 10cm(3.9in) and are coral nippers if their diet is not properly maintained and the proper nutrition given. Same for Flame Angelfish(Centropyge loricula).
Yellow Angelfish are also called False Lemonpeel Angelfish but can be distinguished by the fact that they do not possess the blue eye ring that Lemonpeel's do.
It's a good idea to have a lot of micro algae in your tank when you get the fish as they need a constant supply(like Flame's) and some individuals will not eat anything apart from this algae when first introduced into the tank. This will also help with preventing the Angel nipping at corals as algae is a large part of their diet.
The minimum recommended tank size for one C. heraldi is 70 gallons with the same for C. loricula, though a 55 gallon will work for a single specimen if maintained properly. So for both fish, due to aggression, you're looking at around about 120-150 gallons and even then you're not guaranteed to have a peaceful tank. Angelfish are aggressive to each other no matter what size tank and will have fights occasionally, sometimes you get the ones that are extremely peaceful but on the other hand you also get the ones hell bent on killing each other. It's risk having both in the tank, they could be fine for ages and then suddenly hate each other. So make sure you have a back up plan if you choose to get both.