Balloon molly sickness problems. Whitespot, fungi. Doesn't effect other fish?

I have a sickness-prone balloon molly.

She recently had a mass outbreak of whitespot (is gone now), and now she has a big blob of white (looks like fungi) on her eye.

It is about 2mm diameter and is on the top of the ring around her eye. There is also a very faint white patch around it, and there is a little bit on the eye itself. I've added Fungi-Aid and it's gone down.

None of the sicknesses she's had has had any effect at all on the other fish. And when she had whitespot she got it out of nowhere - I hadn't introduced any new fish for about 2 months.

Will the fungi effect her eyesight?

Any info on why she's so sickness-prone?
Any info on why nobody else has it?
Any info on where she got the illnesses (tank is perfectly healthy!)
Any tips on how to prevent any future illnesses?

Thankyou. :)

keep usin the anti fungi treatment it may take awhile to go completly change 1/2 ur water every 2 weeks .

some people will say this next part is bull but ive hade an bred fish 4 yrs an some have like us a lower ammune system an r more prone to get sick

clear it an keep up the treatment for a little while after 2 make sure

try not to use to much chemicals in ur tank


i dont use any at all just feed em at the same time everyday an clean the filters as needed an change 3/4 of the tanks every 2 weeks

Sounds like icht. The fish should be quarantined. The best way to prevent icth is proper water temperature which should be between 78 & 80 degrees F. So, if you don't have a heater and thermometer you need to get them. They are really cheap. Good luck.