I never tried to breed angels, they just do. I have 13 in a 125 and it happens so random. A twenty would be perfect to put the pair into once they are established. Once the eggs have been laid and fertilized, it can get real dicey as some people leave parents in tank with eggs, and some separate the eggs from parents. The eggs may get eaten, but by leaving parents I'm same tank, they will keep eggs clean. It's a 50-50 situation. If u have a pair, they will more than likely breed over and over. This may give u some opportunities to try different tactics.