1. Education
Send to a Friend via Email
You can opt-out at any time. Please refer to our privacy policy for contact information.

The Basic Fish Groups


View: Amphibians | Birds | Fish | Invertebrates | Mammals | Reptiles | Basic Animal Groups

Fish are aquatic vertebrates that have skin covered with scales, two sets of paired fins, some unpaired fins, and a set of gills. Fish do not represent a single clade but are instead paraphyletic. They include hagfishes, lampreys, lobe-finned fishes, cartilaginous fishes and ray-finned fishes.

Find out more: Fishes

Bony Fish

Photo © Justin Lewis / Getty Images.

Bony fishes (Osteichthyes) are a group of aquatic vertebrates characterized by having a bony skeleton (in contrast to the cartilaginous fishes, a group whose skeleton consists of cartilage, not bone). Bony fishes include two sub groups, the ray-finned fishes and the lobe-finned fishes.

Key Characteristics

The key characteristics of bony fish include:

  • bony skeletons
  • ectothermic
  • gills
  • swim bladder
  • color vision
  • lack placoid scales
  • posess ganoid, cycloid or cetnoid scales

Find out more: Bony Fishes

Cartilaginous Fish

Photo © Michael Aw / Getty Images.
Cartilaginous fish are so named because instead of bony skeletons, their body frame consists of cartilage. Tough and flexible, cartilage provides enough structural support to enable these fish to grow to incredible sizes. Cartilaginous fish include sharks, rays, skates and chimaeras.
  1. About.com
  2. Education
  3. Animals / Wildlife
  4. Fishes
  5. The Basic Fish Groups - Guide to Animal Classification

©2014 About.com. All rights reserved.