I think fishes school for a reason
Like some small fish school because they appear larger to the predators and others school for mates, they don't just school for well... the sake of schooling
To solve this query of whether PBT school in captivity, I think we must first find out why they school in the first place and since it's to drive away other fishes and territorise an area for food, it might not happen in our tanks
The reason, I think, is that the PBT would firstly not face a lack of food and secondly, there is no other place for them to territorise other than the tank itself