Fish Got Ich!

I was bragging about the 30 gal tank that cycled and all fish survived. I spoke too soon, they came down with ick. I bought Nox-ich with malachite green, treated tank at half strength 5 days now(because bottle said use half stength if plecostomus in tank). Tonight I found 2 dead fish that were both active and eating this morning. 1 is white skirt tetra, other neon tetra. I just checked and got ammonia at 0 ppm, nitrite 0, nitrate 20, pH 8.8? I don't understand the 0 ammonia because there is no carbon in filter past 5 days.  pH is usually 8.2.  Any ideas?

 

Did the 2 that died still have ich showing on their bodies? Have you done a water change?
Removing the carbon won't cause the ammonia to spike. Now that the tank has cycled, that will only happen again if you over feed regulary, don't do water changes, or add a bunch of new fish all at once.
If your fish still have ich, try doing a water change, pump the tank temp up by 1-2 degrees and add some aquarium salt according to the directions on the label.

 

I increased the temp, and put carbon back in filter, aquarium salt was always in tank. I have been changing water every other day (about 10 gal) since I started the nox-ich treatment. The white skirt that died still had spots on tail the am before found dead. The neon never had any visible spots. All fish without spots now but glowlight acting sluggish and sitting on bottom of tank. Will salt hurt him? Also do you think it is safe to move pleco to another tank? I have been cycling a 40 gal with driftwood, river gravel and live plants but I don't want to spread the funky fungus. The pleco is probably too big (4 inches)for the 30 gal, I don't have anything larger than 40 gal but at least he will have driftwood and less fish (6 female bettas) to use up his resources.