Assessing Disease

[rust81]

I was wondering whether all fish in a tank would come down with the same illness, or would it be possible for just a few fish to be showing symptoms? In particular, if a fish had white spot would this spread to all the other fish and could some still remain unaffected?

 

[tetraqueen]

White spot does spread rapidly and it depends or how good the others are.
I basically think its like us if there is a cold going at work then most go down with it except for those with extremely healthy immune systems but then if your my hubby he seems resistant whereas if anyone sniffles i catch it.

Other problems do not always spread. Livebearers tend to all get white spot whereas my larger tropicals did not.

Then again was it white spot or stress??

Observation is the best I can offer for saying how others are doing. Remove all infected fish I would say cheaper than a whole new tank.