Bubble eyed betta?

I am not at all a fan of the Tetra medications (all three of them). The only one that would even be worth while for the bacterial infection that is pop eye would be General Tonic, and even that would be far less effective than something like tetracycline (Maracyn TC, TC Capsules) or eryhtromycin + minocycline (Maracyn + Maracyn 2). During treatment, remove any activated carbon from the filter. If treating with tetracycline or minocycline based medications, keep the tank dark, as these drugs degrade with exposure to light, making them more toxic to both the bacteria and the fish.