swelling with scales sticking out is dropsy. This can be cause by a bacterial infection, constipation, or poor water quality. Not knowing your water stats but only the number of fish, I would be inclined to say that it is probably poor water quality. The scales sticking out is caused by retention of water due to organ failure. Sometimes they can come back from it, but often they don't. An epsom salt bath and clean, clean water are the only ways to treat dropsy this far advanced that have had consistent results but even that is no sure thing. fish with dropsy often die.
If it is constipation she will need to be fasted, feeding pea can help.
An internal bacterial infection can be hard to treat. not sure what meds will treat this but they do make medicated foods which may help if she is eating.
A bowl is a bad place for this fish. Bowls are in general bad places for fish, but your tetra is going to need superclean water, meaning filtration and water changes, and a heater to have a chance. Do a large water change in the tank for now, and when you go to the LFS next you need to buy a water test kit (that includes PH, ammonia, nitrIte and nitrAte tests, get a liquid kit with chemicals and vials rather than test strips) and also look at larger tanks. I don't know about the CAE, but the tetras would appreciate a longer tank (say, 20 long) for swimming as they are active fish that prefer to have horizontal space for swimming. Also, larger tanks are much easier to maintain in terms of water quality than smaller tanks, so a little more expensive but very much worth it.