You could fit 2 if it is a taller tank. Angels require more depth than most fish, due to their taller body shape. Many breeders keep pairs in a 20 tall, which measures 12"x24", 16" deep. If the tank is any shorter than that, then don't put them in there. I've heard of breeders keeping pairs in a 15 high, 20"x 10", 18" deep, or keeping 2 pairs in a divided 29 gallon. The height matters more than the length.
Tolak