Any ideas on how long he was in there dead? Cuz if it was only for a short time, the levels shouldnt spike like that and you might need to look for another cause. If he was in there for a while, those would be a normal death spike.
Either way, keep an eye on them. If they dont come down reasonably soon, think water change until the parameters stabilize.
Just to elaborate a bit, I lost a clown in my 20 gal QT which has about 15-20 lbs of LR and 2 cups of LS and he was in the water until I woke up (dont know how many hours he was dead in there, but it was less than 7). I didnt get any ammo or trite spike.
All that to say, check to make sure theres no other source for the ammo.