Difference Cartilaginous and Bony Fishes

Cartilaginous Fishes

  • Cartilaginous fishes are mostly marine.
  • The mouth of cartilaginous fishes is ventral.
  • The external nares are ventral.
  • The scales of cartilaginous fishes are Placoid.
  • In cartilaginous fishes, operculum is absent except chimaera.
  • Caudal fins are heterocercal (asymmetrical).
  • In cartilaginous fishes, cloaca are present except chimaera.
  • Endoskeleton is cartilaginous.
  • Sprial valve is present in the intestine of cartilaginous fishes.
  • Cartilaginous fishes have 5-7 pairs of gills.
  • Swimbladder (air bladder) is absent in cartilaginous fishes.
  • Excretory matter of cartilaginous fishes is Urea.

Difference Bony Fishes

  • Bony fishes are mostly marine and fresh water.
  • The mouth of bony fishes is anterior.
  • The external nares are dorsal.
  • The scales of bony fishes are genoid, cycloid and ctenoid.
  • In bony fishes, operculum is present
  • Caudal fins are usually homocercal (symmetrical).
  • In bony fishes, cloaca is absent.
  • Endoskeleton is partly or wholly bony.
  • Sprial valve is usually absent in intestine of bony fishes.
  • Bony fishes have 4 pairs of gills. 
  • Swimbladder (air bladder) is present in bony fishes. 
  • Excretory matter of bony fishes is ammonia.

CharacteristicsChondrichthyes (Cartilaginous fish)Osteichthyes (Bony fish)
HabitatMainly marineMarine as well as freshwater
SymmetryUsually dorsoventrally flattenedUsually bilateral symmetry
Endo-skeletonCartilaginousMostly bony
Caudal finHeterocrecalHeterocercal or diphyceral
Pelvic finUsually posteriorMostly anterior, occasionally posterior
MouthLarge, crescent shaped on the ventral side of the headVariable shape and size at the tip or terminal part of the head
Gill slitUsually five pairs of gill slits which are not protected by an operculumFive pairs of gill slits protected by an operculum
CloacaA true cloaca is presentIn most bony fishes, the cloaca is absent, and the anus, urinary and genital apertures open separately
StomachTypically J-shapedShape variable. Absent in some
IntestineShort with spiral valve in lumenLong with no spiral valve
LiverUsually has two lobesUsually has three lobes
BrainHas large olfactory lobe, cerebrum and small optic lobe and cerebellumHas small olfactory lobes and cerebrum and large optic lobes and cerebellum
RetinaLacks cone cella pair of cone cells preesnt
EggsA small number of large eggs with plenty of yolkA large number of small eggs with little yolk
FertilisationInternalUsually external
ExamplesScolidon, Electric ray, string ray, SharksLabeo, catla, Hilsa, Wallago, Hippocampus