Yes, whitening of the red area is a sign of the disease. Whilst colour may fade with other diseases, this should be addressed by the treatment with Esha 2000. If it isn't then you can conclude they also are infected, unfortunately.
I would continue the treatment and give those others a chance as they may possibly not be infected. The protozoan that causes this is transmitted by fish eating the bodies of others that have died, so they could be OK.
thanks. I have got 5 in the clove oil stage atm. The coupel of toerhs in the tank two have minor fin rot... should I do those too they show no sign of flufflylstuff or bent spine, after watching from above ... I'll do a 50% change tomororw and let the tank settle for a bit .
You need to change enough water to get the ammonia down to 0.25 or under, treat the tank with a double dose of Prime and repeat this daily until the problem resolves, which it will eventually when the cycle re-establishes. This article has more detail on dealing with ammonia/nitrite spikes: https://www.fishkeeping.co.uk/articles ... ammonia-nitrite-spike.htm