Sorry I'm late, I was just looking at my cories who arrived today
I can't open the file right now, but I may be of help. Does the stomach appear to be flattening out? Are the underbelly scales sticking up? Is its back hunched? Is it flashing? Is one of its fins clamped? Does the fish have dropsy?
If you see these symptoms it may be "unnamed" disease, quite common in livebearers. It has effected my guppies. Epsom salt doesn't work.
And many thanks for the responses folks! I plan on growing my fish family and tanks over time - it's a lot of work, but I seem to enjoy it