Fin Rot On An Angel

[LunaBug]

So I woke up a few days ago to my Angelfish, Bling, swimming backwards and in circles. On further inspection I noticed his left fin and the veil off the dorsal had a white fuzzy edge and some fraying taking place. I figured it was most likely fin rot due to the colder temp of the water since the heater I had blew out about a week earlier. Thankfully none of the other fish were showing signs and I was able to get my hands on some aquarium salt and a new heater. As of today Bling is seemingly making a full recovery. The fuzzy looking white stuff has vanished and he is swimming and eating normally again. Is there anything I can do to try and insure that the other fish don't pick it up and to continue his recovery? 
Tank Specs
36 G Bowfront
81F
gravel
planted
 
Tank Inhabitants
2 Angelfish
2 Bolivian Rams
5 White Cloud Minnows
2 Panda Garra
2 Neon Tetra
2 Ancistrus Pleco (both under 2 in)

 

[Ninjouzata]

Glad he's healing up. Does anyone else have it? Just keep the water clean and they should be fine
 
Also forgive me if I'm wrong but aren't the minnows sub tropical?

 

[LunaBug]

The minnows are in fact sub-tropical but have thrived in the warmer water. I originally had them housed with my betta but they began to outgrow that tank. My theory on them is, as long as they aren't exhibiting signs of stress, are eating regularly, and are growing then they can remain where they are.
So far the rest of the fish are not showing any signs of it, but then again the one who had it, it seemingly sprung up over night. I've been doing water changes of about 25% every other day to help keep the water conditions in check. The latest test showed 0 ammonia 0 nitrites so as far as I am concerned the chemistry isn't an issue at the moment.

 

[Ch4rlie]

The minnows are in fact sub-tropical but have thrived in the warmer water. I originally had them housed with my betta but they began to outgrow that tank. My theory on them is, as long as they aren't exhibiting signs of stress, are eating regularly, and are growing then they can remain where they are.

 
While you say WCMM are sub-tropical and yet you say they are thriving in warmer tropical temps.
 
What actually happens is, like shrimps, if they are in warmer waters, they will not show much, if any, signs of discomfort or stress due to warmer waters, their lives are in fact being fast forwarded. Basically shortening their life span.
 
http/www.seriouslyfish.com/species/tanichthys-albonubes/
 
Says this species is most comfortable at 14 - 22 C (57 - 72 F)
 
Quoted from Seriously Fish
 
"Permanent exposure to warmer conditions is likely to result in a shortened lifespan and in many countries or well-insulated homes it’s best-maintained without artificial heating year-round."
Also,
"Very peaceful indeed and an ideal resident of a well-maintained community  set-up provided its temperature requirements are considered."