Anything Dead should be removed ASAP !!!! Dead flesh will bring ammonia nitrite and nitrates up if there is to much of it and left in the tank for to long.
It also depends if you have hermits that will take care of it quick.
I had my nitrates jump up from 0 to 10 ppm in 2 weeks from a bad batch of tonga snails that went into the sand and most of them died. Luckily i was able to get some of them out as they would come up and die, but im sure some where still left dead in the sand bed and that is why my nitrates went up.
This was about 2 months back and im just now getting it back down to 0, im at 3 ppm now.
SO im sure all the hermits and stuff in the sand took care of the rest but like i said anything Dead left in there for to long will throw your parameters out of wack.
