I don’t have any personal experience with arrow crabs, but as a whole I wouldn’t be too concerned about one going after fish.
That said, it’s a crab and they will eat what they can get their hands on.
I’d pass on neon gobies, clown gobies, and the trimma/eviota gobies.
Most else should be fine.
For a 30 gallon, some good fish are:
Occelaris clownfish
Springers damsel
Tailspot blenny (or other similar blennies)
Any Shrimpgoby + pistol shrimp (get a shrimp that works with the goby like yasha + candy cane or yellow watchman + tiger)
Royal gramma (or any similar basslet)
Firefish
6-line wrasse (they do have a bad reputation for aggression so do watch out)
Possum wrasse
Pink streaked wrasse
Was this biocube originally a freshwater setup? If so, it may not have all of the equipment required for a reef, so extra flow and lighting may be needed. Disregard if this is the one designed for saltwater.