Boesmani Fungal? Quick Reply If Possible Please

[JSmails]

One of my Boesmanis has a white patch on its side with some cottony bits on it. The rest of my tank is fine although I did lose another Boesmani recently. I do not have a hospital tank and the only medication I have in the house is Pimafix. Should I start treatment with this immediately or should I wait till tomorrow and get some other stuff (as Ive not used it before? Will it effect the rest of the tank?

 

[N0body Of The Goat]

Rainbows are supposed to be quite vunerable to columnaris and need signifacant water changes (~50%) at least once a week.

Try and get a decent photo of the white patch, or take the patient to a trusted LFS for diagnosis