Last night I left one of the front glass covers open on the tank and this morning my sixline (first fish I bought in Feb 07) is nowhere to be found. Considering we have two cats I doubt I will ever find him.
Ah man, that stinks. Sorry for your loss. Although its possible he could be hiding. Our watchman goby disappeared for a few weeks then just reappeared one day.
I have a fire goby that disappears for weeks at a time. Just when I am ready to write him off, he miraculously shows up. My yellow coris does the same for days at a time. Hopefully that is what you will find