Possible Fin Rot?

[Teri]

I've just noticed that on 3 of my young guppies, (abt 2 months old) their tails look quite raggedy,and one of them has little left of his. I'm just wondering how this can be possible though, as I have been treating the entire tank with eSHa 2000, as one of the guppies appears to have "shimmies".
Any advice, please?

 

[WILDER]

Water stats in ammonia,nitrite,nitrate,and ph.
Guppys once they start with finrot they seem to go down hill fast, also it could be a secondary infection.
If one of the fry have lost all there tail nearly he's not going to make it sorry, even half of the tail missing they rarely make it.
Have you used the full dose as they are only babies and they might be stessed with the full dose.