I just got off the phone with my girlfriend and she has given me bad news. Mr. Phoomps is dead.
Whatever happened to him took over very quickly because not more than 2.5 days ago he appeared fine. She says that his fin has been eaten down to the bone by whatever was infecting it. And his gill looks like it was infected too. I hope it doesn't spread to the other fish. I may treat with methylene blue when I get home just to controle a bacterial outbreak.