How to tell if something is dead?

Big Habeeb wrote:
Got me a golden headed sleeper goby who I haven't seen for more than a
second or two since adding him (about a week ago). Would I see a
spike of something if he was laying dead someplace???

A week isn't a long time. I'd give it a month before declaring him dead.

Sadly, you often don't find any sign of the missing fish, so you're just
left wondering. The clean up crew will take case of him.

I had a maroon clown fish that would disappear for weeks at a time.
After a while, I just stopped worrying about it.

I also have a feather duster that disappeared within days. 6 months
later I spotted him on the back side of the tank where I don't clean the
glass. Not sure why he's there, but I think he found a good spot to
pick up detritus.

--Kurt