Stupied Cory

[Fizban]

it stays swimming right next to the filter at the top of the tank i tryed to see if i could stop him doing it by giveing him a bit of a scair so i diped my finger in the tank right near him(i no its mean and bad i dont do this sort of thing i just wanted test how stuben he was he still did not move from his spot and he is still there he seems fearless it drives me nuts seeing him just in that one place near the top of the water how long can a cory swim up right for with out stoping ? the other corys are at the bottem of the tank swiming all over what wrong with this other cory