By "as it should be" what do you mean?
Strawberry tetras are albino morphs of black skirt tetras subjected to the cruel methods of fish dyeing. They are much more prone to disease, due to the foreign substance(dye) that their immune system is constantly trying to combat. I doubt that's helping you much.
More info:
http://en.wikipedia.org/wiki/Painted_fish
By swollen, how does it look? White/fluffy? Just bigger?
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current setup:
5.5 gallon low-light planted tank
-nothing....thinking a mini-community.
for reference: my name is Julie