Red Cirlce Underneath Guppy?

[guppyguy25]

there is a red sphere the size of my guppies eye attached to the bottom of my guppies belly.
due to a broken camara i this is all i could come up with sorry

 

[WILDER]

Size of tank in gallons or litries.
How many fish and which type.
Water stats in ammonia, nitrite, nitrate, and ph.

Red patches and bleeding bemeath the skin is septicemia.
Septicemia hard to cure once it progresses as it blood poisoning.
Any signs of flicking and rubbing against objects.
Any whiteness around the sphere shaped patch.