Class: Osteichthyes

These are the bony fishes—ectothermic (cold-blooded) vertebrates adapted to aquatic life with gills, fins, and usually scales--and having a bony skeletal structure (endoskeleton).

Bony fishes are placed into two groups: ray-finned, and lobe-finned.

Ray-finned

Most of the fishes we know of are ray-finned fishes, some examples being: salmon, trout, tuna, eel, and even though it has a lot of cartilage in its skeleton, the sturgeon. One oddity of the ray-finned fishes is the mudskipper, which has fins modified into a kind of suction cup with which it sticks to rocks and logs above the surface of the water.

National Aquarium in Baltimore

National Aquarium in Baltimore

Mudskipper. Aquascape Fish Imports

NOAA

Lobe-finned

Lobe-finned fishes have stubby, fleshy fins which are almost like limbs. Only seven species of lobe-finned fishes are known: The coelacanth, and six types of lung fish. Lungfish take in oxygen by gulping air into a rudimentary lung, which is little more than a sack.

Marbled lungfish. Tadahiro.

Queensland lungfish. Tadahiro.

Coelacanth. Mark Erdmann.