Is this HITH - Oscars?

Following on from my previous posts about salt concentrations, I am sure I
have identified HITH in my Oscars

See pictures at www.geocities.com/thereaperman69 (picture is 51kb) or for
real quick download ww.geocities.com/thereaperman69/index2.html (picture
16kb low quality)

I only really noticed what I believ is the HITH becasue of some white
thingys hanging off the oscars head coming from where those whitish
streaks are marked on the picture.

After adding salt (0.1% / 1000ppm) the next mroning they were gone but the
whitish patches remain - visible from and upward angle catching the lights
full on.

I have found information regarding treating HITH (basically salt, gravel
vac and frequent water change, better and varied diet and reducing stress
and raising temp and failing all those treat for Hexamita)

I just really need confirmation and to know how bad this case is.

Tank setup

1500mm x 600 x 600 or 5 foot x 2 x 2
2 oscar
2 dempsey
2 firemouth
2 peacock

Other fish fine and demspesy spawning every two weeks for last 6!
Oscars eating well but being stressed a little by demspeys during
spawning. Peacocks probably should not be there (I know)

Ammonia 0
ph 7 - 7.4 ish (lost colour chart!)
no other test kits
Will be buying a nitrate kit tomorrow and expect to see elevated levels as
I probably have not been doing water change/ gravel vac as frequently as
I should.

Thanks in advance

Trev