Characteristics :

  • Have a backbone
  • Are cold-blooded, or ectothermic, meaning they cannot produce or maintain their own body heat
  • Live in water
  • Use gills for breathing
  • Have slime, or mucus, glands in skin
  • Most have scales for body covering
  • Have a streamlined body with fins for swimming
  • Most have a row of sensory pores called a lateral line
  • Lay shell-less eggs in water or hatch the eggs inside the female's body
  • Kingdom: Animalia
    • ​Phylum: Chordata
      • Class: Myxini
        • Order:Myxiniformes (hagfish)
      • Class:Cephalaspidomorphi
        • ​Order: Petromyzontiformes (lampreys)
      • Class:Chondrichthyes 
        • Order:Chimaeriformes (chimaeras), Carcharhiniformes (ground sharks - requiem and hammerhead sharks), Lamniformes (mackerel sharks), Orectolobiformes (whale and nurse sharks), Squaliformes (dogfish sharks), Rajiformes (skates and rays)
      • Class: Sarcopterygii
        • Order:Coelacanthiformes (coelacanths), Ceratondontiformes (Australian lungfish), Lepidosireniformes (South American and African Lungfishes)
      • Class: Actinopterygii
        • Order:Polypteriformes (bichirs, ropefish), Acipenseriformes (sturgeon, paddlefish), Lepisosteiformes (gars), Amiiformes (bowfin), Osteoglossiformes (mooneye, goldeye, knifefishes, and arawanas), Anguilliformes (freshwater and moray eels), Clupeiformes (herring, shad and anchovy), Esociformes (pike, pickerel, and mudminnow), Osmeriformes (smelt), Salmoniformes (trouts and salmons), Cypriniformes (minnows), Characiforms (characins (tetras), piranhas, and hatchetfishes), Siluriformes (bullhead catfishes), Cymnotiformes (glass, sand, and ghost knifefishes), Stomiiformes (marine hatchetfishes), Aulopiformes (lizard fishes), Percopsiformes (trout-perches, pirate perch, cave, spring and swamp fishes), Gadiformes (cod, burbot, and hakes), Batrachoidiformes (toadfishes), Lophiiformes (frogfishes and batfishes), Mugiliformes (mullets), Atheriniformes (silversides), Beloniformes (flying and needle fishes), Cyrinodontiformes (pupfishes, topminnow, killifishes, and live bearers), Zeiformes (boarfishhes, dories), Gasterosteiformes (sticklebacks, seahorses, and pipefish), Synbranchiformes (swamp and spiny eels), Scorpaeniformes (lionfishes, scorpionfishes, searobins, sculpin, and greenlings), Perciformes (temperate basses, sea basses, sunfishes, black basses, perch, walleye, darters, drum and many other groups), Pleuronectiformes (flounders and soles), Tetraodontiformes (triggerfishes, boxfishes, cowfishes, puffers, and porcupinefishes)
Student Challenge:
  • Although fish have a streamlined shape, there is variation within this shape. For instance, some are flatter from side to side, and some are flatter from top to bottom. Choose three fish that are found in Kentucky and that have some variation in shape. Determine how these variations help the fish in its special habitat. Make a coloring book to show various fish shapes. Write a caption for each page that explains the adaptation behind the shape. 
  • Interview an experienced angler. What type of fish does he/she like to catch? What kind of bait is used for catching this fish? What information does the angler need to know about the fish's habitat and behaviour in order to be successful at catching it? What regulations apply to the catching of this fish? What source of information does the angler use for learning the regulations? What is the value of this fish to the angler? What is the value of this fish to its ecosystem? Write a magazine article using the information you have learned. Don't forget to give credit to the angler.