Worked like this; I started up my 75 gallon with a boatload of fish from liveaquaria.
Long story short, their stock was terrible, way too young (I wouldn't even consider selling the fish that they did) and 1/4 DoA or dead within days - the rare few survivors had ich (I lost denison barbs to a bout with columnaris too, but that eradicated itself quickly) all within the first week.
Now, those with ich transferred it to my bare bones stock, which was basically a couple of angels and some female bettas / zebra danios.
Due to battling different ailments brought on by the terrible stock from liveaquaria I ended up with my stock divided like this; (the 20 gallon was my original hospital, those fish showing the first signs of ich.. which has slowly showed itself in all tanks now)
75 gallon - 1 male betta, 1 juvenille angel, 4 denison barbs
29 gallon - 6 female betta, 3 oto cats, 10 zebra danio
20 gallon - 2 medium angels, 3 small clown loach
The denisons *cannot* handle heat above 82* I've found. They can and will die. My 20 gallon tank is actually completely cured. It's been running about 15 days now, and signs of ich have long since gone.
Two denisons have 1 white spot each in the 75 gallon.
3 female bettas are showing signs too, very mild.
My question is; how do I treat it at this point? I was thinking of buying another small hospital tank, removing what I have in the 75 gallon into that tank, cranking the heat up to 90+ degrees, overdosing salt and letting it sit like that for 2-3 days which should destroy any ich in the tank. Then at that point I can move what's in the 20, since they are no longer ill - back to the 75. The 29 gallon i'm going to actually keep as an independant tank, but I don't want to kill the otos.. they are young still, but i've kept them alive for about two weeks, and they will probably continue. They are hard to source and harder to keep alive, so I don't want to medicate that tank and kill them.
Any suggestions on where to go from here is appreciated. I really need to move certain stock around, i have one angel terrorizing the other in the hospital tank for one.