It may be a good idea just in case. If you have fresh made water, a heater and a sponge filter or something I would. But he’s already stressed, I would try to get temp to match or slow drip acclimation just to reduce stress. If you have some melafix it may give some temporary relief to the ammonia burns is that’s what it is. Also air stone if you done have sponge should help too. The breathing fast is because gills get burned, so the more oxygen in the water the better in my opinion.
good luck my friend. I hope your able to figure out what’s going on, I know it’s sucks when you know something wrong but dont know what. I’m hoping for the best outcome for you