Help! Is This Fin Rot?

[FishyFriend101]

Hi I just came back from a three day vacation in BC and noticed that my fish is missing it's tail and thought it might be fin rot or nipping from the other fish. I looked up pictures of fin rot and saw that they kind of looked like my other fish just more severe. Please check to see if you think any of these pictures have fish with fin rot. If it is fin rot how can I cure it?
 
My water quality is all fine except for about 0.1 ammonia
 
Thanks

 

[Dreamer03]

It looksmore like they were biting each others tail off...but fin rot you jist need to buy a medication at any petstore. Its cheap

 

[SarahMarie]

One of my platys had a ripped fin. Just make sure the water is pristine. Mine is looking a lot better now after I increased my water changes