sae`s....ill

hello everyone

i have 3x sae`s which i have had for approx 6 months now.the biggest is 3 inch,the middle one 2.5 inch and the smallest is 2 inch.
the biggest one has a scab on the back of it`s head,and a bulging eye.
the middle one has gone pale from it`s dorsal to it`s tail,and may have swelling around it`s pelvic area.
the little one has no obvious problems.....but is rather lethargic(to a lesser extent to the other 2).
iv`e added a 2 or 3 new plants recently,so i suppose i could have introduced something with them.
i`ve also started dosing iron(3 weeks on 1 week off)currently on week 5)...and looking back,i`m not 100% certain the sae`s did`nt react ever so slightly,the first time i dosed.
my params are unchanged at nil,nil,40....and all other tank occupants are behaving normal.
iv`e done a 33% water change this evening(normal schedual is 33% per week)and there`s not much else i can do now,as i won`t be back home untill saturday morning.
temp is 25 and my water is v hard.

any thoughts or comments appreciated.....thanx