There are always crayfish in this one pond where the fiance and I go hiking. The first time I saw them I thought they were shrimp.

Let’s check out the difference between shrimp and crayfish.

Definitions:

• Shrimp: any of several small, long-tailed, chiefly marine crustaceans of the decapod suborder Natania, certain species of which are used as food.
• Crayfish: Also called crawdad, crawdaddy. Any freshwater decapod crustacean of the enera Astacus and Cambarus, closely related to but smaller than the lobsters; any of several similar marine crustaceans, especially the spiny lobster; also, crawfish.

And, because I was wondering:

• Decapod: Any crustacean of the order Decapoda, having five pairs of walking legs, including the crabs, lobsters, crayfish, prawns, and shrimps.

Shrimp:

• Most are under 8 inches long.
• Live in freshwater or saltwater.
• Can be found on sandy or muddy bottoms.
• The most common in the US are white, brown, or pink.
• There are over 1,900 varieties.
• Are a good source of protein, and are low in fat and calories.
• Are high in cholesterol. 

Crayfish:

• Are usually 3 to 4 inches long.
• Nearly all live in freshwater. 
• Are active at night and crawl along the muddy bottom.
• Can be white, red, brown, orange, dark green, or black.
• There are over 500 types.
• Are a good source of protein, and are low in fat and calories.
• Are high in cholesterol.
• Are also called crawfish.

Prawns and lobsters are also in the crustacean family along with shrimp and crayfish, so of course we have to investigate these guys as well.

Prawns:

• Are typically smaller than shrimp and crayfish.
• Are closely related to shrimp.
• Live in freshwater or saltwater.
• They basically are shrimp, except for a technical difference with an abdominal flap.

Lobsters:

• Are much bigger than shrimp, crayfish, and prawn.
• Closely resemble crayfish, because of the claws.
• Live in salt water.
• The spiny lobster is considered to be a crayfish.

As we can see, shrimp and crayfish differ slightly in size, habitat, and appearance. Prawns resemble shrimp, and lobsters resemble crayfish.

Nutritionally, shrimp and crayfish are virtually the same. How about flavor, then?

My Food Substitutions Bible does indicate that you can switch out shrimp and crayfish for one another in recipes. However, it does recommend subbing prawns for jumbo shrimp, and crayfish for rock shrimp.

Mark Bittman in How to Cook Everything puts shrimp and crayfish together in the same explanation: “I include crawfish (also called crayfish) in this section. Although, many devotees of that shellfish believe them to be not only different from shrimp but superior to them. I find the two greatly interchangeable (in all ways except peeling, which is more tedious for crawfish).”

Clearly, the two are incredibly similar and can be used for one another in cooking.

Personally, I have never tried crayfish. However, there are many recipes that call for shrimp and crayfish – I assume if you’re putting the two together in the same dish they must each bring out something different in the taste buds.