Deep Sea Viperfish
(By David Csepp, NMFS/AKFSC/ABL (http://www.photolib.noaa.gov/htmls/fish4036.htm) [Public domain], via Wikimedia Commons)
The Viperfish is a very scary fish with his long teeth that stick out of his mouth. These sharp teeth become so big that they even grow close to its eyes. It's without a doubt a great predator that combines speed and strength to kill its prays. The attack of this fish only takes a fraction of a second, just as a real viper.
The Viperfish has one long dorsal spine with at the end a photophore that gives light. Many deep sea creatures uses these photophores to attract other fishes and this is no exception. By switching its photophore "on" and "off" it attracts other prays, but in the deep sea, it's sometimes hard to tell if it's a pray or a predator.
These little fishes look very ferocious, but aren't so ferocious as they seem to be. The Viperfish can only grow up to 30 cm in length and a lot of creatures could just eat this fish in one bite. The colour of the Viperfish variates from green to silver, black and even blue. There are also some photophores located at the bottom of the Viperfish, these camouflages the fish from possible predators from below and could also serve as communication with others. It also serves to lure prays or to find a mate.
(By David Csepp, NMFS/AKFSC/ABL (http://www.photolib.noaa.gov/htmls/fish4037.htm) [Public domain], via Wikimedia Commons)
The Viperfish swings its long dorsal spine over its head to attract the attention of possible prays, just as the Angler Fish. Another special thing is that the Viperfish can store a lot of food in its long stomach. Feeding is sometimes a big problem and certainly on depths of 1.600 meters where they stay during daytime. Therefore they move to shallow waters at night brake. Moving to shallow waters (600m) provides more food for the Viperfish (little fishes, shrimps, ..), but more food means more danger. The Viperfish greatest predators are dolphins and sharks who live in the shallow water zone. Luckily they have a basal metabolic rate that helps them to survive for many days without eating.
The reproduction of Viper fishes is still a mystery and some hypotheses exist, for example some scientists believe that they are external spawners (the female releases her eggs in the water to be fertilized). Once the eggs hatch, the larvae of the Viperfish are approximately 6mm long. The age of a Viperfish is still one big mystery, but some think they can live for over 30 years and others 40 years. Catching or even seeing these animals alive is very rare because of the great depths they live in. Some people have tried to hold these fishes in specialized aquaria, but without any success. The environment they live in, is just to difficult to obtain.