Frontosa are predators, they don't require a veggie diet. The only way a Frontosa is going to get bloat is if it is kept in VERY poor conditions. Frontosa can get FLOAT, a different problem than bloat, but also due to stress/poor conditions.
Float is also more common in wild caught fronts. If they guys catching them bring them up to fast then their swim bladder gets ruined and stress causes it to act up.