No, angelfish do not mate for life. In the wild, angelfish usually only pair up for one mating period. In captivity, however, they may stay with the same mating partner for a while. This is mainly due to the lack of options.
After a while, they might grow apart and choose new partners. If one of them dies, the surviving mate might hesitate to find a new partner for a while.
You’ll know a pair of angelfish is partnered up if they often swim together in a space they’ve claimed. They’ll also defend each other when other angelfish attack one of them or enter their territory.
