Teleost

The teleosts or Teleostei (Greek: teleios, "complete" + osteon, "bone") are by far the largest infraclass in the class Actinopterygii, the ray-finned fishes, and make up ninety-six percent of all fish. This diverse group arose in the Triassic period and members are arranged in about 40 orders and 448 families. Over 26,000 species have been described. Teleosts range from giant oarfish, measuring 25 ft (7.6 m) or more, and ocean sunfish weighing over 2.0 long tons; 2.2 short tons (2 t), to the minute male anglerfish Photocorynus spiniceps, just 0.24 in (6.2 mm) long. As well as torpedo-shaped fish built for speed, teleosts can be flattened vertically or horizontally, be elongated cylinders or take specialised shapes as in anglerfish and seahorses. Teleosts dominate the seas from pole to pole and inhabit the ocean depths, estuaries, rivers, lakes and even swamps.