Dead fish. Crabs tend to be detritus eaters, so if it's a chunk of something organic, they will try to eat it. As for a living fish, if the crab can catch the fish, the crab will try to eat the fish.
Here is the thing...
hermit crabs dont live in water so they cant be eaten by fish but....
MARINE HERMITS CRABSMARINE HERMIES LIVE UNDER WATER BUT YOU SHOULD..... N.E.V.E.RFEED HERMITS TO FISHstar fish eat dead crabs and small slow moveing sea creatures
A few varieties of catfish, bass, and pike
fish do eat crabs like the bigger predators (Halibut, Cod, etc.)
Puffer fish
sheephead fish
birds, fish and sea otters
seagulls, crabs, some fish, seastars
Birds, some fish, ect...
crustean eats dead fish or crabs and lobsters
The Great Blue Herons eats small fish, such as shrimps and crabs
It eats jellyfish, fish , crabs ,and plants.
oxygen (air) and water
The box jelly fish eats fish crabs and other animals and People.
crabs,worms,clams,small fish, and crustaceans
Crabs eat green seaweed Whelks eat red seaweed Small fish eat shrimps Shrimps eat plankton Animal plankton eats plant plankton Sea anemones eat plankton Shore crabs eat shrimps and small fish Crabs eat whelk Small fish eats sea anemones Seagulls eat small fish and crabs
It depends to what type of fish food.