Yes, bristlenose plecos can live alone. Bristlenose plecos are solitary fish, so they don’t need tank mates to keep them company. They can live alone in the tank with no problems.
Moreover, bristlenose plecos, especially males, are highly territorial towards each other. If there isn’t enough space, food, or mates, bristlenose plecos won’t hesitate to fight each other. Thus, you should try to keep just one bristlenose pleco per tank, especially if you’re a beginner or have limited space.
With that said, solo bristlenose plecos are perfect for community tanks. They’re calm and mild-mannered towards other species. Just make sure to pick equally docile tank mates to avoid conflicts in the tank, for example: