URGENT!! Need Help, Black Spot & Transparent Blob in YUMA

[YGPR]

I have been fragging my yuma and all this time is fine
just now, my yuma has black spot spawning on the edge of polyp and it excretes transparent blob
I siphon the blob out but the next day it excrete it again
I have 2 yumas a days ago that did (Black Spot and The Blob) that as well and it dies (I siphon the blob out)

What do i need to do??
Is the blob is defence mechanisme so i dont need to siphon it?

I tried to use betadine (iodine) dip as well but no works
If this a disease, i am very afraid it infects my others yuma

Here the pics
Blob already siphoned but the yellow line is the reference of the blob size

Thanks in advance

 

[cdemoss01]

Id reccomend you tag Vetteguy or fishdocters.