r/Guppies

This Guppy was gifted to me and he has been confusing me ever since. His body looks kind of Endler-like but his tail fin says otherwise. Is he a hybrid or just an interesting looking Guppy-mutt?

He's also not interested in my other Guppys at all. He's busy bullying my Mollys instead.

(This is the best picture I could get. He's very unphotogenic)

one of my male guppies had this melting texture on his tail after an ammonia and nitrite spike (it was a 0.5 spike for both it's now getting better currently at 0.02 or less) should I do something or just wait.