Has my guppy got fin rot

[Owp]

Hi,
Recently my guppy tail looks like it might have fin rot. Can anyone tell if it is?

 

[Angellove78]

Umm, yeah, I'd think so. Unless it's a new breed. What did he look like before?

 

[Owp]

He looked fine before with a smooth edged tail one of the other fish has a bit of a jagged tail too

 

[Angellove78]

Melafix, good stuff!