Missing fish?

[Sunee]

4 fish is too many for a 14 gal bio cube IMO - most people recommend only 2 or 3 small fish for one.

You should do some more research on the lobster - they can get quite large up to 5" - much too large for a biocube.

I did a quick search and found on multiple sites:
Caution must be taken when incorporating into a reef aquarium, as it may harm small fish and invertebrates.

I would consider 1" fish small so was probably a casualty of the lobster.