I don't think the SeaChem Paraguard is going to help. It's used to treat external protozoan infections and the fish shows no signs of that.
Typical symptoms associated with external protozoan infections include:
fish rubbing on objects
cream, white or grey patches on the head or body (Costia, Chilodonella, Trichodina)
white spots on body or fins (Ichthyophthirius)
gold sheen on body (Oodinium, aka velvet)
These symptoms get worse over a week or two and eventually the fish dies. Your fish has been breathing weird for a few weeks and has no other symptoms associated with external protozoan infections.
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Bars of soap can have perfume in them. Smell the soap and if it smells "Spring Fresh" or lavender or anything really, then it probably has perfume in and you should rinse your hands well under running water before working in the tank.
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I'm with Deanasue in relation to water changes. Just try doing big daily water changes and gravel cleaning the substrate. Make sure any new water is free of chlorine/ chloramine before it's added to the tank.
Feed the fish more often with a variety of food to try and build him up physically. Then see how he goes over the next couple of weeks.