African clawed frog with spots

[suewenking]

I have an african clawed frog who periodically gets spots on her back.
It does not appear to bother her and they usually disappear after a few days.
She lives in a six foot aquarium with another ACF (who does not suffer this) and several catfish. They all get on extremely well so I do not think it is anything to do with the cats.
Anyone have any ideas

 

[spAcE mOnkEy]

maybe they are nipples.

nah, i have no clue what they are.