White dot in one of my discus eye

[nimbusv]

last night i made a 50% Water change and everyone was fine, but this morning i saw one of my discus with a little white spot on his right eye, his other eye is fine, he's eating fine, normal behaviour.

Water parameters are:

Ammonia = 0
Nitrite = 0
Nitrate = 20
Ph 7.0
GH 6

I add 2 pics of him

http://img22.photobucket.com/albums/v67/nimbusv/discus2.jpg

http://img22.photobucket.com/albums/v67/nimbusv/discus1.jpg

Sorry about the quality, but i was already late for work.

I added melafix before leaving for work in case it's just a scratch.

Any ideas what it is and how can i treat it????

[Annie]

Looks like it could ne "cloudy eye" starting. For starter I would get the water vonditions to a "Pristine Condition".
The cloudy eye may go away with these "pristine" conditions,
(even though the tank conditions should already be great) you need to keep everything on the money and no slack. ...I would try that and see before having to medicate. You then could try Melafix before hitting the more severe meds.

[Proteus]

Ditto to Annies suggestion...

increase the water change regime, give the filter sponges a good rinse in old tank water, keep the floor well vacuumed (no waste, excess food lying around) then next step would be Melafix, even perhaps a little amount of aquarium salt...

that should do it... (fingers crossed)