Diamond Watchman Goby has disappered!

[Mechaninano]

So I got a Diamond Watchman Goby about a week ago and for the first three days he was going about digging his burrow and seemed to be acclimating quickly. Then on the fourth day I didn't see him at all. day five same thing and the sand had started to grow more algae. Concerned that he may have been crushed by a caved in rock I started to remove them from the sand bed. I moved all 5 rocks and shifted the sand around and found no sign of him.
Is it possible something has eaten it??
Here's what is in the tank (That I know of lol)
Yellow Watchman Goby (1/2 the size of the Diamond)
Emerald Crab fairly large
3 inch green bubble tip anenome
2 inch black ice snowflake clown
all of the above is smaller than the Diamond by at least an inch or more

If anyone has any advice it would be greatly appreciated. I would hate to have a dead fish poison the tank now.

25 gallon tank currently
90 gal. setup in progress