No, celestial pearl danios are not aggressive. Celestial pearl danios are actually shy and docile. When housed with other species, they spend most of their time hiding behind aquatic plants at the bottom of the tank.
For this reason, celestial pearl danios are a wonderful addition to a community tank consisting of peaceful fish, such as guppies, goldfish, tetras, and cory catfish.
However, while they’re not considered aggressive, male celestial pearl danios can be persistent when it comes to mating. They will chase the females relentlessly, creating a stressful environment. It’s highly recommended to maintain a two-to-one female-to-male ratio.