Well, normally by now I'd see something from rbishop on the subject of cycling so instead I just pulled this off one of his other posts.
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Fishless cycling:
Just as it sounds, you can establish the cycling environment without any fish. This method does not pose any threat to fish, establishes a large bacteria colony allowing full stocking upon completion and gives you time to decide on what fish you want.
When establishing a tank with this method, you will use a source of ammonia to initiate the nitrogen cycle. After your tank is set up, add water and treat for chlorine/chloramines. Your filtering systems and heaters should be in place and operating to your satisfaction.
Add ammonia to bring the tank to a concentration of 5 ppm. The amount you add will vary with the size tank you have. Do not be in a rush. Add small amounts and test, repeating as necessary. If you get it too high, you can drain and refill.
Now the hurry up and wait part happens. Every two days, test your ammonia level in the tank. When the ammonia levels start dropping, add additional ammonia as required to keep the ammonia at 3-4 ppm, start daily testing and test for ammonia and nitrites. Nitrites should be developing as ammonia goes away. This first stage could take 1-3 weeks.
When you see the test results showing Nitrites, start maintaining your ammonia at the 2-3 ppm range. The nitrites increasing reflect you are in to the second stage. Continue daily testing for ammonia and maintain the tank in the 3 ppm range. You will see nitrites climb so high they will be off the scale for a reading. This will continue for one to two weeks and it will seem the nitrites are never going to go away.
There will be a day where you test and the nitrites have completely disappeared, thus, the bacteria that convert them to nitrates have established themselves. When you see this drop to zero on nitrites, dose ammonia in the tank to about 5 ppm, and wait 24 hours. If at the end of that period, ammonia and nitrites are zero, your cycle has been established. Test for nitrates, and do a 75-90% water change. Pull your water down to 20 ppm nitrates and add the fish! If you have to wait to get your fish, keep the cycle established by dosing more ammonia, but you may have to do another water change before adding your fish.
Personally speaking searching for it and cut and pasting it was so much easier than trying to type all that out myself. Just to go back to the start of it more than likely ich didn't directly lead to your fish death. This seems to be a case of ammonia / nitrite poisoning in a new aquarium. As other have stated in a properly cycled aquarium you should see ammonia 0ppm, nitrite 0ppm, and nitrate < 40 ppm. You can also take the time to properly do a fishy cycle, but that would entail starting your aquarium with only about 3 fish and building up slowly from there taking upwards of 2 months between the adding of fish.
