The Strangest Fishes in the World

Mudskipper
Mudskippers are amphibious. They could live in the water and out of water. You could see the video of the mudskippers fighting outside the water.
They are found in tropical, subtropical and temperate regions.

World's Weirdest : Fish Battle on Land
http://www.youtube.com/watch?v=aAz7iMcC8e0

Flying Fish
Flying fish can fly out of water for more than 200 meters with the height up to 6 meter to escape from their predator such as the Swordfishes with their long wing-like fins. Its flying speed is 70 km/hour.
Just look the video of Flying Fish here:
http://www.youtube.com/watch?v=9uFjmeWnFZ4

Seahorse

This fish called Seahorse because it looks like a horse. Seahorses are unique. They are monogamous and mate for life. They are among the only animal species on Earth in which the male bears the unborn young.

Barreleye a fish with transparent head... Barreleyes inhabit moderate depths, from 400 to 2,500 metres down.
Fish With Transparent Head Filmed
http://www.youtube.com/watch?v=Zoygy-8PTtU

Reference:
http://en.wikipedia.org/wiki/Mudskipper
http://en.wikipedia.org/wiki/Flying_fish
http://en.wikipedia.org/wiki/Seahorse
http://animals.nationalgeographic.com/animals/fish/sea-horse/?rptregcta=reg_free_np&rptregcampaign=20131016_rw_membership_n1p_intl_se_w#
http://en.wikipedia.org/wiki/Barreleye