Difference Between Oysters and Mussels (with Table)

Oysters and mussels are shellfish that belong to the family of mollusks. Both the animals are typically farmed or harvested to be eaten as seafood.

Oysters are also known for their ability to produce natural pearls. Mussels have this ability to produce pearls as well, however, it is rare for them to do so.

The difference between oysters and mussels is that oysters have rough, dull, and hard shells that are covered in barnacles while mussels have smooth, purplish-black shells that are oblong shaped and have elongated ends.

The shell of an oyster is generally oval-shaped. While its inner surface tends to be white in colour, its outer surface may be dark grey, white, blue, purple, or brown.

Comparison Table Between Oysters and Mussels

Parameters of ComparisonOystersMussels
Shape of shellOysters have an oval-shaped shell.Mussels have a thin oblong-shaped shell with elongated ends.
Texture of shellThe shells of oysters are rough, hard, and covered in barnacles.The shells of mussels are smooth for easier movement through mud or sand.
ColourThe inner surface of an oyster shell is white or pearl-colored while the outer surface may be dark grey, white, blue, purple, or brownThe inner surface of a mussel shell is silvery or pearl-colored while the outer surface can be purplish, black, or brown.
SizeOysters are bigger in size than mussels.Mussels are among the smallest of the mollusk family.
Living environmentOysters live in marine (salty) water which calcifies their shells; however, they may also set up habitat in brackish waters of rivers and seas.Mussels commonly live under brackish water; they form symbiotic colonies in which these animals depend on each other to survive.
Body structureOysters tend to be fleshier than mussels.Mussels have feet while oysters don’t; however, mussels choose to stay immobile.
UsesOysters are farmed to be eaten as seafood and also for their pearls; being filter feeders, oysters can filter around five liters of water per day.Mussels are farmed for food; however, it is rare for them to produce pearls; mussels are known to be a great source of protein.
Edible speciesSome edible varieties of oysters include dredge oyster, rock oyster, Pacific oyster, Ostrea angsi, etc.Some edible varieties of mussels include Mediterranean mussels, California mussels, Perna Perna, Perna Viridis, etc.

What are Oysters?

Oysters are bivalve mollusks that mostly live under marine water but are sometimes found in rivers and seas as well. Their oval-shaped shells are hard, rough, and covered in barnacles.

Oysters have been a food option for people since prehistoric times. Their cultivation is known to have begun from the times of the Roman Empire. At present time, they are considered a delicacy for their wide range of flavor profiles and rich nutrient content.

The fertilization of oysters takes place internally. They self-fertilize and produce millions of eggs in about six hours only. These eggs develop into larvae that attach to a host for survival. Subsequently, they find a permanent habitat for themselves where they can fully mature.

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Oysters have many varieties and species. Interestingly, their taste depends on the environment that they live in. Some of the edible varieties of oysters include European flat, Pacific Oyster, Olympia Oyster, Kumamoto, Dredge Oyster, Rock Oyster, etc.

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What are Mussels?

Mussels are edible bivalve mollusks that are commonly found in brackish water. They have smooth shells that are oblong shaped and elongated ends. The color of their shells tends to be purplish, black, or brown.

Mussels commonly grow up as males and end up turning into females. The fertilization of these shellfish takes place externally. Mussel eggs turn into larvae and attach themselves to the fins and gills of other fish. When they grow up, they tend to live in symbiotic colonies in which they depend on each other to survive.

Mussels fix themselves to rocks and other surfaces using threads which are referred to as ‘byssal’ threads. These threads are known to have great strength. At present, scientists are even trying to develop an adhesive from mussels to be used during eye surgery.

There are about 17 species of mussels that are fit for human consumption. Some of the edible varieties of mussels include Blue Mussels, California Mussels, Mediterranean Mussels, Pinna Carnea, Perna Perna, etc.

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Main Differences Between Oysters and Mussels

  1. Oysters have oval-shaped shells that are rough, dull, and covered in barnacles while mussels have smooth shells which are oblong shaped.
  2. Mussels tend to be purplish-black or brown in colour while oysters are most commonly dark grey, black, white, or brown.
  3. Oysters tend to be larger in size than mussels.
  4. Oysters are found in marine as well as freshwater while mussels tend to set up habitat in freshwater more often.
  5. Oysters tend to be fleshier than mussels.
  6. Even though both the animals are mostly immobile, mussels have feet while oysters don’t.
  7. Males and females are separate in the case of oysters while mussels can be male and female both.


Oysters and mussels have many similarities. Both belong to the mollusk family and are often confused for one other. However, a great way to tell them apart is by their shells. While the shells of oysters are irregular and rough, mussels have a smooth shell which makes it easier for them to move through mud or sand.

Both the shellfish have been used as a food source since prehistoric time. Even though oysters are the pricier delicacy between the two, mussels are making their way onto gourmet menus nowadays as well. This is because of how quick and easy they are to make.


  1. https://www.tandfonline.com/doi/abs/10.1080/13657300309380348
  2. https://www.sciencedirect.com/science/article/pii/S0889157515002021