Red Platy With Scab On Back

[bearfreeman]

Hi,

I have a Red Platy with scab on back, shares tank with black mollies, neons, & large 'sucker fish' who seem okay. Any ideas?

 

[The-Wolf]

what kind of scab?
what are your water parameters?
what is this sucker fish?

 

[WILDER]

What colour is the scab and how big is it.