Types of Shellfish: Weird, Wonderful, and Downright Confusing
Apr 21, 2021 | 3 minute read Comments
Reading Time: 3 minutes

When you think “Shellfish,” the things that come to mind are clams, scallops, oysters – you know, things that live in shells. For the most part, you’d be right. However, there are a lot of types of Shellfish out there, and some of them are sure to surprise you. With that in mind, let’s take a dive into the weird and wonderful world of Shellfish species.

A giant clam with a brown shell and a bright blue inside underwater on the seafloor. Giant clams are one of the biggest types of Shellfish.

The two main types of Shellfish are Crustaceans and Mollusks. Crustaceans are more straightforward, because pretty much everything we eat falls into one sub-family. Mollusks are a little more tricky. So, let’s start with the simple stuff and work our way up to the weirdness.

Crustaceans: the Tanks of the Ocean (Mostly)

A yellow crab on a beach with its arms raised

The Crustacean family includes many of our favorite foods. Lobster, Crab, and Shrimp are all Crustaceans, as are Crawfish for you freshwater types. The thing that they all have in common is their hard outer “exoskeleton.” As anyone who’s eaten them knows, Crustaceans don’t have bones. Instead, their shell acts as armor, keeping their tender bodies safe.

As well as delicious seafood, the Crustacean family has a few species you might not expect. Ever scraped your foot on a barnacle? That’s a Crustacean. Remember “sea monkeys”? Guess what, turns they’re not monkeys at all – they’re brine shrimp, another type of Crustacean. Some of them don’t even live in water – woodlice are also from the same family. 

Mollusks: Shellfish Without Shells?

Mussels on a rock, with green seaweed below and blue water above

If you were surprised by some of the Crustacean family, just wait until you meet the Mollusks. This group includes a fair few fishy favorites, but it also has some creatures you’d never describe as Shellfish.

1. Bivalves. Cue the list of your favorite seafood: Mussels, Oysters, Scallops, Clams, Cockles (people eat those, right?). The thing that they all have in common is that their shells have two halves. That, and the fact that they taste great.

2. Gastropods: These guys are your typical seashell that you’ll find on a beach. Sea Snails, Whelks, Conches, and Limpets are all Gastropods. They’re less common in restaurants than their two-halved cousins, but some, like Abalone, are delicacies.

3. Cephalopods: Yes, Squid and Octopus are both types of Mollusks. You may be thinking, “How can they be Shellfish? They don’t have a shell!” Actually, they do. The difference is that, instead of growing a hard shell around them, they developed a tough plate inside called a “gladius.” Essentially, they’re inside out.

An illustration of a kraken attacking a sailboat in a storm
Pictured: Shellfish

So what have we learned today? Shellfish aren’t fish, and they don’t always have shells. Many of us have kept them as pets, and ancient sailors were scared of them destroying their boats. The one thing we can agree on is that this is a strange and confusing family. That, and that lots of them are delicious!

What are your favorite Shellfish to eat? Were you surprised by any of the species on our list? Let us know in the comments below!

Comments (2)
  • Ijeva Bambridge

    Nov 22, 2020

    How about Hokkai Clam?

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      Nov 23, 2020

      Hi Ljeva,

      How about them? Never tried them myself – any good?

      All the best!

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