Mardel Coppersafe has some of the worst reviews from experienced hobbyists. It kills your benefitial bacteria. Stays in the water for up to a month because carbon wont take it out, and the threshold between toxic to fish and toxic to parasites is very slim.
Ive seen this condition before. Its probably just a birth defend because it is a parrot, But i have seen fish in water that has a low oxygen level, The gills will enlarge and look rather unpleasent. Only use meds if you 100% positively know what your dealing with.