Classification Of Fish And Shellfish

Fish can be classified three different ways:

• Vertebrate or invertebrate: Vertebrate fish or finfish have fins and internal skeletons; invertebrate fish, or shellfish (mollusks and crustaceans), have external skeletons.
• Saltwater or freshwater
• Lean or fatty

FINFISH:

• Fresh Water : Lean / Fatty 
• Salt Water :  Lean / Fatty 

SHELLFISH

• Crustacean : Crab, Crayfish, Lobster and Shrimp

• Mollusk : 

1. Bivalve : Clam, Mussel, Oyster, Scallop
2. Univalve : Abalone, Conch, Snail
3. Cephalopod : Octopus, Squid