| Marine and Freshwater both | Mostly marine |
| Usually bilaterally flattened | Usually dorsoventrally flattened |
| Mouth is terminal on head | Mouth is mostly ventral |
| External nares are dorsal | External nares are ventral |
| Caudal fins are homocercal (or diphycercal) | Caudal fins are heterocercal |
| Operculum present, no spiracles | No operculum, pair of spiracles |
| Cloaca are absent | Cloaca are present, except in Chimaera |
| Endoskeleton is partly/wholly bony | Endoskeleton is cartilaginous |
| Placoid scales | Cosmoid, Ganoid, Cycloid or Ctenoid scales |
| Swim bladder is present | Swim bladder is absent |
| Excretory matter is ammonia | Excretory matter is urea |
| Numerous, small eggs with less yolk | Few, large eggs with large amount of yolk |
| Cones are present in retina | Retina lacks cones |
| Conus arteriosus absent | Conus arteriosus present |
| Brain is advanced with smaller olfactory lobes | Brain is primitive with larger olfactory lobes |
| Goldfish, trout, koi, piranha, seahorse, cod, salmon | Sharks, rays, skates, sawfish, chimeras |