Викисловарь says that креветка is animate -- and therefore the accusative plural is креветок, like the genitive.
But it seems to me there might be a complication: because of their small size, I would tend to guess that shrimp are treated as a "mass noun" (like изюм, "a pile of raisins"), rather than a "count noun" (like арбуз, "a watermelon"). And from Googling, it seems that LIVE shrimp are "count," but COOKED shrimp are "mass". Thus, in the context of eating in a seafood restaurant:
В ресторане я покушал креветку.
--- At the restaurant, I ate (a big pile of many) shrimp. (NOT "exactly one individual shrimp").
В ресторане я покушал креветки, потом попросил у официанта, "Можно «doggy bag», чтобы взять остатки с собой?"
--- At the restaurant, I ate some (of the big pile of many) shrimp, then asked the waiter, "Can I have a «doggy bag» to take the leftovers with me?"
In the second sentence, креветки isn't an "inanimate accusative plural"; it's a "genitive singular" that expresses a partitive meaning.
But in the context of countable living shrimp:
На море я пытался ловить креветок, а в конце концов я поймал лишь одну креветку.
--- At the seashore I tried to catch shrimp (anim. acc. pl.), but in the end, I caught only one shrimp (acc. sg.).
P.S. In English, we'd generally use the plural "shrimps" only when discussing different species. Otherwise, it's a "mass noun" only, whether they're alive or cooked.