flying fish

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various marine fishes of the family Exocoetidae, having enlarged, winglike pectoral fins capable of sustaining them in brief, gliding flight over the water.

from The Century Dictionary.

• noun Any fish which can sustain itself or make a flight through the air by means of enlarged and wing-like pectoral fins.
• noun A small constellation of the southern hemisphere, Piscis Volans. Some-times simply Volans.

from the GNU version of the Collaborative International Dictionary of English.

• (Zoöl.) A fish which is able to leap from the water, and fly a considerable distance by means of its large and long pectoral fins. These fishes belong to several species of the genus Exocœtus, and are found in the warmer parts of all the oceans.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tropical marine fish of the family Exocoetidae, having enlarged winglike pectoral fins enabling it to escape predators by taking short gliding flights through the air.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun tropical marine fishes having enlarged winglike fins used for brief gliding flight