I keep the temps up for two weeks just to be sure but watch the danio's cus they don't always cope too well with the warmer temps. A great article on ich can be found here:
fish aren't doing so good my danios look very stressed and my tetra seems to be getting worse as the one with the bad infection is gasping pretty heavily now not sure how many fish will make it through this ich infection but it dun look too good
What temperature do you currently have the tank set up at and have you provided some additional air to compansate for any temperature rise?
If you have the temps up to 32 degrees then like my previous post said the danios will not cope too well. If this is the case start to bring the temp down by two degrees which will help with the stress.
Here is a link that gives a good explanation of ICH and all the different treatments you can use.
I'm sorry for your loss I'm not sure what else you can do except maybe if you added the appropriate meds since the higher temp seems to be taking its toll. Also, I was under the impression that salt was needed in the tank to kill off the ich, that the higher temp just hastened the life cycle so they were in the free swimming stage more often. But I could be wrong. I think catfish don't tolerate salt well, though. I'm really not sure what to tell you, except I'm sorry, & goodluck.