This category contains all freshwater and saltwater fish.

Fish are gill-bearing aquatic craniate animals that lack limbs with digits. Most fish are ectothermic ("cold-blooded"), allowing their body temperatures to vary as ambient temperatures change. There is no one class that contains all fish, so this page will only classify them as far as Vertebrata. With 33,100 described species, fish exhibit greater species diversity than any other group of vertebrates. Fish are classified as such:

  • Kingdom: Animalia
  • Superphylum: Deuterostomia
  • Phylum: Chordata
  • Subphylum: Vertebrata
  • Class: Actinopterygii
    • OR
  • Class: Sarcopterygii

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