Sounds pretty bad, the peeling scales and bloating is a disorder/disease called "Dropsy", when the scales start to peel it generally means there is little hope left for the fish and the fish is suffering from general organ failure.
Dropsy can be caused by numerous things, it basically starts off when the fishes osmotic internal process goes wrong and the fish starts to hold lots of fluid in its body, which as the fish becomes more and more bloated the fishes scales start to have the "pine cone" look as they stick out or fall off.
The swollen anus is a symptom of internal parasites.
Personally i would advise euthanising the fish as there is little hope for it, dropsy is a difficult problem to treat even when it is in its early days, and when the scales pine cone there is little hope at all. It is best to put the fish to sleep. Because the fish is only a small guppy, i would advise using something like the freezing water submersion method or something like that, the articles below on humane forms of fish euthanasia may be of interest to you;
http
/www.fishforums.net/index.php?showtopic=8031
http
/www.fishforums.net/index.php?showtopic=207212
How many fish do you have and what types in your tank and their sizes roughly? How many gallons is your tank and its measurements? How long has the tank been set up for?
I would treat the tank as a whole for internal parasites as such parasites are very infectious and can be lethal if left untreated, most meds which contain metronidazole or levamisole are very effective are treating internal parasites in fish. A med like Fish Zole would be good;
http
/cgi.ebay.co.uk/Fish-Zole-Metronidaz...VQQcmdZViewItem
