Bizarre fishes from the Deep Sea

Among the deepsea fishes, there is one order called the Lampridiformes, which includes large brightly colored pelagic fishes. There are two extreme body forms, the opahs (Lampridae), and the oarfish (Regalicidae). The oarfish are distinguishable because they are long, extremely attenuated and reach lengths of 8 meters! The anterior rays of the dorsal fin and the pelvic rays are highly modified - you just have to see them to believe it.

Another oddity about the oarfish is that they maintain position vertically in the water column. The link to oceanfootage.com has a series of video clips to see this rare creature swimming. Note: the oarfishes are likely responsible for many sea-serpent stories.

The opah, or moonfish, is deepbodied and laterally compressed. It is a solitary fish and most frequently encountered in tuna fisheries.

Neither of these families is on your "need-to-know" list. However, when you encounter an unknown fish anywhere in the world, you can use the family key to fishes at FishBase to identify it.