no..its not athletes foot....depending on your age..health and history...it could be a number of things but its wise to get it checked out by your gp
Swelling or edema can be caused by heart problems...best you get this checked for the reason you are retaining fluid in feet and ankles. Also liver damage or disease can cause a person to retain fluids. Kidneys need to be looked at.
Do not delay, if you have not seen a dr about this yet. They need to rule out other serious health conditions.