Also known as the "ogrefish," the fangtooth is one of the deepest living fish currently in existence, found at around 16,000 meters (approx. 10 miles) below sea level in every ocean in the world. As hardly anything else lives so deep in the ocean, fangtooth has very little to eat and so is almost constantly in a state of starvation. Because of this lack of food, it has evolved to have a permanently open jaw so it can eat anything that crosses its path. I can't say it's making deep sea diving very appealing.
The fangtooth fish is thankfully only around seven inches in length. But about six-and-a-half of those inches are pure terror.
I'm not going to say anything about this one. Just one look at this photo has got me praying for help.
2. Pacific viperfish