his mouth is opening while hes breathing heavy too

I dont know what was wrong but hes acting normal again... i didnt do anything was setting up for a fresh water dip. but i dont think theres a need now what do you think?

It's flukes. Use some Praziquantal if you can purchase some. If you find some I can tell you how to use it. Oh and you need some vodka since prazi doesnt mix well. Flukes will fall off of the host to drop eggs so there may be a period of 5-7 days of your fish being normal then the eggs will hatch and flukes appear again. So you need to use prazi..wait 5 days..repeat.