hospital cycle

Last dose of Oliver's treatment with PraziPro was monday. Tuesday I did several partial wc to remove the medication. He still looks fine- eats eagerly, good color, no clamped fins.White thing on his body unchanged. I had not been doing daily checks of the water quality during treatment, since I didn't want to fret about it too much and was doing twice-daily wc on his tank anyway. This morning I tested the parameters- Ammonia 0.25, Nitrite 0.5, Nitrate 5. So crap, the hospital tank is cycling. Doing another wc right now. Later today I'm going to anesthetize the fish and get a close look at the thing on him w/the loop. I don't want to just pull it off if it's some kind of parasite that has a head buried under his skin. If it's something just hanging on w/hooks like anchorworm, that might be the right thing to do...