Angelfish is a shoaling species and that means it needs a group. Five is considered absolute minimum, but more will usually avoid more serious aggression issues which are almost inevitable with fewer than five. Males establish a territory, in in any tank 4-feet in length or under it will be the tank space. A group of five in a 4-foot length tank is absolute minimum, but there is no guarantee. Individual fish can decide to do things differently, they do not necessarily adhere to the norm for the species. As in all animals, including humans.
Spawning is likely to occur with male/female present, and this presents more challenges and problems. Two rival males are not likely to last long in this small a space. If a pair spawns, the other angelfish may have to be removed. A "pair" may spawn, but if they do not accept each other and actually bond, the "pair" will not last long before the female (usually) is dead. A bonded pair (they have accepted each other from a large group of angelfish) might work very well in a 65g.
Tankmates. Never small linear fish, like cardinal tetras for example. Round disk-shaped peaceful characins can work, depending upon the temperament of the angelfish. Rosy Tetra and similar species. Nothing that is active swimming (angelfish are sedate and do not appreciate hyper fish around them), nor prone to fin nip.
I post this video in almost every response on this issue. This is how angelfish should be maintained, if you want to provide what the fish "expect." You will see continual nudging and challenges, not a problem here because there is a group of 11 angelfish and the tank has space for them. Though in the comments the owner says he considers this tank too small and plans another.
