Shrimp eat fish

Shrimp that eats fish is a problem.
Especially if that fish can be eaten by people.
If you wonder Where Do All the Little Fish Go?
...forage fish or ‘small pelagics’, make up a huge part of the global catch. 
All those anchovy, sardines, menhaden, herring, and other small shoaling fish can add up to roughly a third of all the fish landed, and the majority are not destined for direct human consumption.