Welcome to the forum.....
When a fish is kept in poor conditions and suffer ammonia burns during the healing process they can develop scar tissue especially in the gill area and this in turn can cause breathing problems and oxygen exchange issues-depending on how bad/much scar tissue the fish may always be somewhat lethargic or laid back
In your filtered tanks I would increase the water changes to twice weekly 50%...1-50% water only and 1-50% to include the substrate by vacuum or stir and dip method to maintain water quality
In the unfiltered tank-twice weekly water changes...1-50% and 1-100% to maintain water quality
Both fish could benefit from a 10 day treatment IMO
The lazy one needs Epsom salt and the spastic one needs aquarium salt
Epsom salt 2tsp/gal along with 100% daily water changes for 10 day while in QT, water temp 76-78F
Aquarium salt 1tsp/gal along with 100% daily water changes for 10 days while in QT, water temp 76F
You can float the small QT containers in the heated tanks to maintain water temp for the 10 day treatments
If you have tannins to add all the better of either IAL or dried Oak leaf
Pre-mix the treatment water in a 1gal jug of dechlorinated water-add the proper amount of salt and tannins-shake well before use and use this water for the 100% daily water changes.....
If you have access to mosquito larva-offer them-most fish will always eat live foods...nutrition is really important part of the healing process to build the immune response and overall health....
Good luck and keep us posted......